A house kept warm to shelter tender plants and shrubs from the cold air; a place in which the plants of warmer climates may be reared, and fruits ripened.
- A heated greenhouse for plants that require an even, relatively warm temperature.
- An environment conducive to vigorous growth or development; a hotbed: "With its mix of African, Latin, European, and pan-American influences, the Caribbean is truly a musical hothouse” ( New Yorker).
- Grown in a hothouse: a hothouse orchid.
- Delicate and sensitive, as if from being grown in a hothouse.
- To cultivate in a hothouse.