hotbed

Estimated CEFR level: C2 — Proficiency

Estimated from word frequency; not an official CEFR classification.

Definition

noun a situation that is ideal for rapid development (especially of something bad)
noun a bed of earth covered with glass and heated by rotting manure to promote the growth of plants

From hot + bed.

Regular hotbed of it lately. — Ulysses, James Joyce
That's what he said--'a hotbed of rebels.' — The Long Roll, Mary Johnston
It appears to regard all novel superstitions, and especially foreign worships, as the hotbed of sedition and disloyalty. — Studies in Literature and History, Alfred C., Sir Lyall

Type a word, a sentence, a book title, or a link to an English article. WordNet and the Classics answer.

Try

A library of classics · a vault of words · instant etymology & meaning