WordNet Dictionary- [adj] marked by acquiring or amassing; "we live in an accumulative society"
- [adj] increasing by successive addition; "the benefits are cumulative"; "the eventual accumulative effect of these substances"
Webster's 1913 Dictionary\Ac*cu"mu*la*tive\, a. Characterized by accumulation; serving to collect or amass; cumulative; additional. -- {Ac*cu"mu*la*tive*ly}, adv. -- {Ac*cu"mu*la*tive*ness}, n.