A hothouse is a heated greenhouse where plants grow in warm, controlled conditions even when it's cold outside. Gardeners use hothouses to grow tropical plants in places where winter would normally kill them, or to raise vegetables and flowers out of season. The glass walls let in sunlight while trapping heat inside, creating a miniature climate that feels like spring or summer year-round.

The word also describes an environment so sheltered and controlled that it's almost too perfect. When people talk about a hothouse environment, they usually mean a place so protected from normal challenges that the people in it might struggle when they face real difficulties. A school that never lets students fail or work through problems might be called a hothouse: the students grow in carefully controlled conditions but might not develop the resilience needed for harder situations later.

Sometimes hothouse describes something that develops very quickly under intense conditions. A hothouse atmosphere in a laboratory might produce rapid discoveries, while a hothouse political climate means tensions and changes are happening fast. The image is of forced growth: everything happening faster and more intensely than it would naturally.