trampoline

Concise Oxford English Dictionary © 2008 Oxford University Press:
trampoline /ˈtrampəliːn/

▶noun a strong fabric sheet connected by springs to a frame, used as a springboard and landing area in doing acrobatic or gymnastic exercises. ▶verb (usu. as noun trampolining) do exercises on a trampoline.

– derivatives
trampolinist noun.

– origin C18: from Ital. trampolino, from trampoli ‘stilts’.