Autism refers to a Pervasive developmental disorder characterized by abnormalities in social functioning and in Language and communication, and by unusual interests and behaviors. More specifically, autism affects every aspect of the child's interaction with his or her world, involves many parts of the brain, and undermines the very traits that make us human_our social responsiveness, ability to communicate, and feelings for other people.
Autism is also known as Autistic Disorder.
Other /More definition:
Autism refers to a serious developmental disorder in which one of the major symptoms is the withdrawal of contact from other people. People with autism typically do not make eye contact with others and have difficulty telling what emotions others are experiencing in social situations. It is a severe disorder involving very poor communication skills and very deficient language development; a disorder, with an onset before the age of 30 months, that involves severe social and communicative impairment and may or may not be accompanied by mental retardation An autism spectrum disorder is characterized by extreme aloneness, communication problems, intolerance of change, and ritualistic behavior. Children with Autism fail to relate to others, communication problems, intolerance of change, and ritualistic behavior.