Entry 1 sense Webster, 1913 Bicentenary /bīs-ĕn'-tĭn-ĕrˌ-ē/ · Bi·cen·te·na·ry · IPA /baɪsˈɛntɪnˌɛriː/ 01 a. Of or pertaining to two hundred, esp. to two hundred years; as, a bicentenary celebration. 1. Of or pertaining to two hundred, esp. to two hundred years; as, a bicentenary celebration.