on the spectrum UK /ˌɒn ðə ˈspɛktɹəm/US /ˌɑn ðə ˈspɛktɹəm/ prepositional phrase[after a verb]1 •(informal) Having autism spectrum disorder or exhibiting traits relating to or within the autism spectrum; autistic.This sensitivity leads me to understand that there are sections that may not be appropriate for some, particularly younger people on the spectrum. — 2002