a construction in which an expected grammatical agreement in form is replaced by an agreement in meaning, as in The crowd rose to their feet, where a plural pronoun is used to refer to a singular noun.
Origin: 1890–95; < NL < Gk sýnesis understanding, intelligence, equiv. to syn-syn-+ (h)e- (s. of hiénai to throw, send) + -sis-sis
syn·e·sis (sĭn'ĭ-sĭs) n. A construction in which a form, such as a pronoun, differs in number but agrees in meaning with the word governing it, as in If the group becomes too large, we can split them in two.
[Greek sunesis, union, understanding, from sunīenai, to understand, bring together : sun-, syn- + hīenai, to send, hurl; see yē- in Indo-European roots.]