- a developmental disability of highly variable presentation, commonly characterized by social and communication differences, repetitive behaviors, intense specialized interests, and differences in sensory processing; autism spectrum disorder.
- (no longer in clinical use) a developmental disability that commonly manifests in early childhood, characterized by repetitive or restricted behaviors, differences in understanding social interactions, and delayed development of linguistic and cognitive abilities: formerly contrasted with Asperger syndrome.
- a developmental disorder whose symptoms include difficulty in responding conventionally to people and actions and limited use of communication
