A note on language
Language around disability and neurodiversity evolves. Many autistic people prefer identity-first language ("autistic person") while others prefer person-first language ("person with autism"). Dictionaries reflect the era they were written in; more recent entries tend to use more current, respectful terminology. All definitions below are presented for reference and scholarly comparison.
Autism / ˈɔː.tɪ.z(ə)m /
noun · medical / psychology
The word "autism" derives from the Greek autos (self), coined by Swiss psychiatrist Eugen Bleuler in 1911 to describe self-referential thinking in schizophrenia, and later adopted by Leo Kanner (1943) and Hans Asperger (1944) in its modern sense.
A variable developmental disorder that appears by age three and is characterized especially by difficulties in forming and maintaining social relationships, by impairment of the ability to communicate verbally or nonverbally, and by repetitive behavior patterns and restricted, stereotyped activities and interests — see Asperger syndrome, autism spectrum disorder.
Merriam-Webster further notes: "The term is sometimes used informally as short for autism spectrum disorder."
1. A lifelong developmental condition characterized by difficulties in social interaction and communication, and restricted and repetitive patterns of behaviour, interests, and activities. It is a spectrum condition that affects people in different ways and to varying degrees.
2. Historical / Psychiatry. Self-centred or inward-directed thinking, especially in schizophrenia (the sense first used by Bleuler, 1911). Now chiefly of historical interest.
A developmental condition, present from early childhood, that makes it difficult to form relationships and communicate with other people, and causes a limited range of activities and interests.
A developmental disorder characterized by impaired communication, limited social interaction, repetitive behaviour, and restricted interests. It usually appears before the age of three.
Collins also lists: autistic (adj.) — "of, relating to, or affected with autism."
A condition that affects the way the brain works, causing difficulties with communication and social skills, and sometimes leading to repeated patterns of behaviour.
A pervasive developmental disorder that typically appears during the first three years of life and is characterized by markedly abnormal or impaired development in social interaction and communication and by a restricted repertoire of activity and interests. Also called autistic disorder, classical autism, infantile autism, Kanner syndrome.
Origin: 1910–15; from Greek autós self + -ism.
A developmental disorder of variable severity that is characterized by difficulty in social interaction and communication and by restricted or repetitive patterns of thought and behaviour.
A neurodevelopmental disorder marked by (a) deficits in social communication and interaction, including deficits in social reciprocity, in nonverbal communicative behaviors, and in establishing and maintaining relationships; and (b) restricted, repetitive patterns of behavior, interests, or activities, including stereotyped or repetitive motor movements or speech, insistence on sameness, highly restricted and fixated interests, and hyper- or hyporeactivity to sensory input. Symptoms are present from early developmental period. It encompasses conditions formerly known as autistic disorder, Asperger syndrome, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS).
Diagnostic criteria require: A. Persistent deficits in social communication and social interaction across multiple contexts; B. Restricted, repetitive patterns of behavior, interests, or activities; C. Symptoms must be present in the early developmental period; D. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning; E. These disturbances are not better explained by intellectual developmental disorder or global developmental delay.
Specifiers include: with or without accompanying intellectual impairment; with or without accompanying language impairment; associated with a known medical or genetic condition or environmental factor; associated with another neurodevelopmental, mental, or behavioral disorder; with catatonia.
Autism spectrum disorder (ICD-11: 6A02) is characterized by persistent deficits in the ability to initiate and to sustain reciprocal social interaction and social communication, and by a range of restricted, repetitive, and inflexible patterns of behaviour and interests. The onset occurs during the developmental period, typically in early childhood, but symptoms may not fully manifest until later, when social demands exceed limited capacities. Deficits are sufficiently severe to cause impairment in personal, family, social, educational, occupational or other important areas of functioning.
Autism, formally known as autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition characterized by differences in communication and social interaction, and restricted and repetitive patterns of behavior and interests. Autistic people may also experience differences in sensory processing (e.g., high or low sensitivity to sensory stimuli). Autism is considered a spectrum condition because of the wide variability in type and severity of symptoms. The neurodiversity paradigm views autism as a natural variation in human neurology, not a disorder to be cured.
Wikipedia also notes significant debate around the medical model vs. the social model of disability, and identity-first vs. person-first language preferences within the autistic community.
Autism Spectrum Disorder / ˈɔː.tɪ.z(ə)m ˈspek.trəm dɪˈsɔː.də /
noun phrase · medical / psychology · abbrev. ASD
The term "spectrum" was formally incorporated when the DSM-5 (2013) collapsed several previous distinct diagnoses — autistic disorder, Asperger syndrome, childhood disintegrative disorder, and PDD-NOS — into a single diagnosis.
Any of a group of developmental disorders (such as autism and Asperger syndrome) that are marked especially by difficulties in social interaction, by impairment of the ability to communicate verbally or nonverbally, and by repetitive behavior patterns and restricted, stereotyped activities and interests.
A range of closely related conditions in which a person shows patterns of behaviour and development associated with autism, varying in the nature and severity of their effects. The spectrum includes conditions formerly classified as Asperger syndrome, high-functioning autism, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS).
A range of conditions characterized by challenges with social skills, repetitive behaviours, speech, and nonverbal communication. ASD encompasses what used to be considered separate conditions, including autistic disorder (classic autism), Asperger syndrome, childhood disintegrative disorder, and PDD-NOS.
Autism spectrum disorder (ASD) is a broad term now used by both the DSM-5 and ICD-11 to describe a heterogeneous group of neurodevelopmental conditions sharing core features of atypical social communication and restricted/repetitive behaviors. Prevalence estimates range from approximately 1 in 36 (CDC, 2023) to 1 in 100 people globally (WHO), with variation attributed to differences in diagnostic criteria, methodology, and awareness. Some scholars and advocates prefer "autism spectrum condition" (ASC) as a more neutral, non-pathologizing framing.
In DSM-5, the single diagnostic category that replaces the previously separate diagnoses of autistic disorder, Asperger syndrome, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified. The "spectrum" concept reflects both the heterogeneity of presentations and the range of functional impact.
Neurodiversity / ˌnjʊər.əʊ.daɪˈvɜː.sɪ.ti /
noun · sociology / psychology · coined c. 1998
Coined by Australian sociologist Judy Singer in 1998, popularized by journalist Harvey Blume the same year. The term frames neurological difference as natural human variation rather than deficit.
The condition of having a brain that functions in ways that diverge significantly from the dominant societal standards of "normal." Also: individual differences in brain functioning and behavioral traits, regarded as part of normal variation in the human genome.
The range of differences in individual brain function and behavioral traits, regarded as part of normal variation in the human genome. The term is especially used in the context of autism spectrum conditions, dyslexia, ADHD, and related conditions.
The idea that neurological differences between people — such as those caused by dyslexia, ADHD, autism spectrum conditions, and other conditions — represent natural, valuable human variation, and that neurodivergent individuals bring distinctive strengths.
The variation in human brain function and behavioural traits, including autism, ADHD, dyslexia, etc., viewed as part of normal human variation and not as disorders.
Neurodiversity is the concept that neurological differences are normal and natural forms of human diversity. The neurodiversity paradigm challenges the pathologization of conditions such as autism, ADHD, dyslexia, dyspraxia, dyscalculia, bipolar disorder, synesthesia, and others. Coined by Judy Singer (1998), the term gained wide usage following Harvey Blume's article in The Atlantic the same year. It underpins the neurodiversity movement, which advocates for social acceptance and accommodation rather than cure or normalization.
The term encompasses both a descriptive claim (brains differ) and a normative claim (this difference is natural and valuable).
"The world would be a poorer place without the autistic mind. This is not to romanticize autistic suffering, but to recognize that neurodiversity is part of what makes humanity rich."
— Simon Baron-Cohen, Zero Degrees of Empathy (2011)
Special Needs / ˈspeʃ.əl niːdz /
noun phrase (plural) · education / social policy
A term primarily used in educational and social welfare contexts. Many disability advocates prefer more specific language, noting "special needs" can be vague or patronizing. The preferred term in UK policy contexts is increasingly "additional needs" or "additional learning needs" (ALN).
Any of various difficulties (such as a physical, emotional, behavioral, or learning disability or impairment) that causes an individual to require additional or specialized services or accommodations (as in education or recreation).
The particular educational needs of children with physical disabilities or learning difficulties, or the needs of adults with such disabilities. Often used attributively: special needs children, special needs education, special needs assistant.
Requirements for specialized support — typically educational, therapeutic, or practical — arising from a physical, developmental, sensory, or intellectual disability. Originally applied chiefly in educational policy contexts; latterly extended to adult social care.
Usage note: The term is contested. Some disabled people and advocates prefer "additional needs" or disability-specific language. UK government documents since 2014 use "special educational needs and disability" (SEND).
The particular educational requirements of children who have physical or mental difficulties, or of adults with such difficulties. Also: the care or provision required by people with such difficulties.
Requirements that arise because of physical, mental, or emotional conditions that make it difficult for some people to learn, work, or live in the same way as others.
The required special accommodations and services for a person with a physical or mental disability or learning disorder, or for a person with a social or emotional problem: a child with special needs; special needs education.
Special needs (or special educational needs, SEN) is an umbrella term used in education for students who require support beyond the standard curriculum or school environment. In the US this is often formalized through an Individualized Education Program (IEP) under IDEA. In the UK, the Children and Families Act 2014 uses "special educational needs and disability" (SEND). The UN Convention on the Rights of Persons with Disabilities (CRPD) advocates for inclusive education rather than segregated "special" education. Many advocates note that the term can stigmatize and prefer language that specifies the person's actual needs or diagnosis.
Disability / ˌdɪs.əˈbɪl.ɪ.ti /
noun · law / medicine / social sciences
1. A physical, mental, cognitive, or developmental condition that impairs, interferes with, or limits a person's ability to engage in certain tasks or actions or participate in typical daily activities and interactions.
2. A disadvantage or deficiency, especially a physical or mental impairment that prevents or restricts normal achievement.
1. A physical or mental condition that limits a person's movements, senses, or activities.
2. Law. A legal incapacity; a restriction on a person's legal capacity to act. Also: a disadvantage imposed by law.
3. A thing that puts one at a disadvantage; a handicap.
The OED notes the medical/social model distinction: the medical model locates disability in the individual's impairment; the social model locates it in barriers created by society.
In the International Classification of Functioning, Disability and Health (ICF), disability is an umbrella term covering impairments, activity limitations, and participation restrictions. Disability is the interaction between individuals with a health condition and personal and environmental factors. It is not merely a health problem — it is a complex phenomenon, reflecting the interaction between features of a person's body and features of the society in which they live.
Disability is the experience of any condition that makes it more difficult for a person to do certain activities or have equitable access within a given society. Disabilities may be cognitive, developmental, intellectual, mental, physical, sensory, or some combination of these. A disability may be present from birth, acquired during a person's lifetime, or both. Disability studies scholars distinguish between the medical model (disability as a personal deficit), the social model (disability as caused by societal barriers), and the biopsychosocial model (disability as the interaction of impairment and environment), among others.
ADHD / ˌeɪ.diːˌeɪtʃˈdiː /
noun · abbrev. · Attention Deficit Hyperactivity Disorder
A neurodevelopmental disorder that typically appears first in childhood and is characterized by persistent inattention, hyperactivity, or impulsivity that interferes with functioning or development — abbreviated ADHD. It includes three presentations: predominantly inattentive, predominantly hyperactive-impulsive, and combined.
Attention deficit hyperactivity disorder: a condition characterized by difficulty in controlling behaviour and paying attention, and by constant activity. Children with ADHD are often impulsive and have trouble sitting still or focusing on tasks.
A persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development, as characterized by: Inattention — six or more symptoms (five for adults 17+) including failing to give close attention to details, difficulty sustaining attention, not listening when spoken to directly, not following through on tasks, difficulty organizing, avoiding sustained mental effort, losing things, being easily distracted, and forgetfulness; and/or Hyperactivity and impulsivity — six or more symptoms including fidgeting, leaving seat, running/climbing in inappropriate situations, inability to engage in leisure quietly, being "on the go," talking excessively, blurting out answers, difficulty waiting, and interrupting.
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, impulsivity, and/or hyperactivity that is disruptive and inappropriate for an individual's developmental level. It is one of the most commonly diagnosed neurodevelopmental disorders in children, and often persists into adulthood. Like autism, ADHD is considered part of the neurodiversity umbrella by many advocates. Approximately 5–10% of children and 2.5–5% of adults are estimated to have ADHD.
Intellectual Disability / ˌɪn.tɪˈlek.tʃu.əl dɪsˈæb.ɪl.ɪ.ti /
noun phrase · medicine / psychology · formerly "mental retardation"
A condition of significantly below-average general intellectual functioning with deficits in adaptive functioning that first manifests during development. Generally indicated by an IQ of 70 or below. Sometimes called intellectual developmental disorder in DSM-5.
A condition characterized by significant limitations in both intellectual functioning (reasoning, learning, problem-solving) and adaptive behavior (practical, social, and conceptual skills), originating before the age of 18. The preferred clinical term replacing the now outdated and offensive "mental retardation."
Intellectual developmental disorder (intellectual disability) is a disorder with onset during the developmental period that includes both intellectual and adaptive functioning deficits in conceptual, social, and practical domains. Three criteria must be met: A. Deficits in intellectual functions such as reasoning, problem-solving, judgment, abstract thinking, academic learning, and learning from experience, confirmed by clinical assessment and standardized intelligence testing; B. Deficits in adaptive functioning that result in failure to meet developmental and sociocultural standards for personal independence; C. Onset during the developmental period.
Intellectual disability (ID), also known as intellectual developmental disorder (IDD) or general learning disability, is characterized by significant limitations in intellectual functioning and adaptive behavior, originating before age 18. It is classified by severity: mild (IQ 50–70), moderate (IQ 35–50), severe (IQ 20–35), and profound (IQ under 20). Causes include chromosomal abnormalities (e.g., Down syndrome), genetic conditions, prenatal exposure to toxins, birth complications, and environmental factors. Down syndrome is the most common identifiable cause of intellectual disability.
Disorders of intellectual development (ICD-11: 6A00) are a group of etiologically diverse conditions originating during the developmental period, characterized by significantly below average intellectual functioning and adaptive behavior approximately 2 or more standard deviations below the mean, based on appropriately normed, individually administered standardized tests.
Developmental Disability / dɪˌvel.əpˈmen.t(ə)l dɪsˈæb.ɪl.ɪ.ti /
noun phrase · law / medicine / social policy
Any of a diverse group of severe, chronic conditions that arise before age 22 from mental or physical impairment or both, which result in substantial limitations in several areas of major life activity such as self-care, learning, mobility, self-direction, receptive and expressive language, or capacity for independent living.
A condition resulting from a physical or mental impairment, or a combination of both, that appears before a person reaches adulthood and results in limitations in functioning.
Developmental disability is a diverse group of chronic conditions that are due to mental or physical impairments arising before adulthood. Developmental disabilities cause individuals to have significant limitations in areas of intellectual functioning and adaptive behavior. These conditions can include intellectual disability, autism spectrum disorder, cerebral palsy, epilepsy, and fetal alcohol spectrum disorders. The US Developmental Disabilities Assistance and Bill of Rights Act (DD Act) defines it as a severe, chronic disability attributable to mental or physical impairment manifested before age 22 and likely to continue indefinitely.
Inclusion / Inclusive Education / ɪnˈkluː.ʒ(ə)n /
noun · education policy / social sciences
The act or practice of including students with physical or mental disabilities in the general classroom; the belief that all students, regardless of disability, should attend and participate in age-appropriate regular education classes in their neighborhood schools and receive the supports and services necessary for them to succeed.
In education, the principle and practice of educating pupils with special educational needs or disabilities alongside their mainstream peers, with appropriate support, rather than in segregated, specialist provision. Distinguished from mere "integration" (physical presence) by the emphasis on full participation and belonging.
Inclusive education is the process of strengthening the capacity of the education system to reach out to all learners. It is grounded in the belief that the regular school is the most effective means to combat discriminatory attitudes, create welcoming communities, build an inclusive society, and achieve education for all. Schools that operate inclusively are the foundation of a compassionate society.
Inclusion in education refers to ensuring that students with disabilities are educated in the same classrooms as their non-disabled peers, with appropriate supports. This contrasts with mainstreaming (partial integration) and exclusion in segregated settings. The UN Convention on the Rights of Persons with Disabilities (CRPD, Article 24) enshrines inclusive education as a right. Research literature generally supports inclusion as beneficial for both disabled and non-disabled students when implemented with adequate resources and training.