Entry 3 senses · 2 variants Webster, 1913 Bicentennial · Bi·cen·ten·ni·al · IPA /ˌbaɪsɛnˈtɛnɪəl/ a. n. 01 a. Consisting of two hundred years. 1. Consisting of two hundred years. 2. Occurring every two hundred years. 02 n. The two hundredth year or anniversary, or its celebration. 1. The two hundredth year or anniversary, or its celebration.