Entry 1 sense Webster, 1913 Accumulative /ək-yo͞om'-yəl-ātˌ-ĭv/ · Ac·cu·mu·la·tive · IPA /əˈkjum.jəˌleɪ.tɪv/ 01 a. Characterized by accumulation; serving to collect or amass; cumulative; additional. 1. Characterized by accumulation; serving to collect or amass; cumulative; additional.