Cumulate is a verb that describes the action of gathering or accumulating things over a period of time to form a larger quantity or mass. Some synonyms for cumulate includes accumulate, amass, collect, hoard, stockpile, and pile up. These words can be used interchangeably in sentences such as "Over the years, John has accumulated a vast collection of rare books" or "The company has been stockpiling supplies in preparation for the upcoming project." The use of synonyms such as these can help to add variety and interest to writing, while still conveying the same meaning.