conservatory

Concise Oxford English Dictionary © 2008 Oxford University Press:
conservatory/kənˈsɜːvətri/

▶noun (pl. conservatories)

• 1 Brit. a room with a glass roof and walls, attached to a house and used as a sun lounge or for growing delicate plants.

• 2 N. Amer. another term for conservatoire.

– origin C16: from late L. conservatorium, from conservare (see conserve).