Third person singular present tense: gathers together, accumulates, or heaps up; increases progressively.
From Latin 'cumulare' + '-s' third person singular marker; the verb form describing the action of accumulating in present tense for he/she/it.
Cumulates is less common than 'accumulates,' but scientists and formal writers use it when they want to sound more technical or when they need the specific connotations of 'heaping' or 'gathering' that accumulate doesn't quite capture.
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