Etymology
Advertisement
cumulative (adj.)

c. 1600, "formed by adding to, increasing inorganically" (a sense now obsolete), from Latin cumulatus, past participle of cumulare "to heap," from cumulus "heap" (from suffixed form of PIE root *keue- "to swell") + -ive. Meaning "increasing by successive additions" is from 1640s (implied in cumulatively).

Related entries & more 
Advertisement
*keue- 
*keuə-, Proto-Indo-European root meaning "to swell," also "vault, hole."

It forms all or part of: accumulate; accumulation; cave; cavern; cavity; coeliac; church; codeine; coelacanth; coeliac; coelomate; concave; cumulate; cumulative; cumulus; enceinte; excavate; kirk; kymatology; Kyrie eleison.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit svayati "swells up, is strong;" Greek kyein "to swell," koilos "hollow, hollowed out, spacious, deep;" Latin cumulus "a heap, pile, mass, surplus;" Lithuanian šaunas "firm, solid, fit, capable;" Middle Irish cua "hollow;" Armenian soyl "cavity."
Related entries & more 
accumulative (adj.)

"tending to accumulation; cumulative," 1650s, from Latin stem accumulat- (see accumulate) + -ive. Related: Accumulatively; accumulativeness.

Related entries & more