Define segregated. segregated synonyms, segregated pronunciation, segregated translation, English dictionary definition of segregated. v. seg·re·gat·ed , seg·re·gat·ing , seg·re·gates v. tr. 1. To separate or isolate from others or from a main body or group. See Synonyms at isolate. 2. To cause (people or institutions, for example) to be separated on the basis of race, sex, religion, or another factor.