A hothouse is a heated building, usually made of glass, in which plants and flowers can be grown.
N-COUNT
（尤指思想或感情活動的）爆發地，溫床
You can refer to a situation or place as a hothouse when there is intense activity, especially intellectual or emotional activity.
例句
The vast crowds make Rome a frantic hothouse at times.熙攘的人群有時將羅馬變成一個癲狂情緒的爆發地。...the reputation of the College as a hothouse of novel ideas.該學院享有的新思想搖籃的美譽