Pullulus

Part of speech: noun

Definitions

1. To breed or produce in large numbers
2. to be born or hatched in abundance, especially in a quick or prolific manner
3. to thrive or multiply rapidly, often referring to small organisms or young forms of life

Etymology: In Latin, "pullus" meant a young animal, especially a chick or foal, and "pullulus" is its diminutive, a little young one. The Latin verb "pullulare" grew from that idea, describing shoots sprouting or creatures swarming in numbers, as young things tend to do. English took the verb as "pullulate" in the 1600s, keeping the sense of rapid multiplication, especially of microbes, insects, or new growth. The noun "pullulus" itself is not used in English. The sense you've given belongs to the verb. Related English words come from the same root: "pullet," a young hen, arrived through Old French "poulet," a diminutive of "poule," hen, which descends from Latin "pullus."