springboard

Concise Oxford English Dictionary © 2008 Oxford University Press:
springboard/ˈsprɪŋbɔːd/

▶noun

• 1 a strong, flexible board from which a diver or gymnast may jump in order to gain added impetus.

• 2 a thing providing impetus to an action or enterprise.

• 3 Canadian & Austral. a platform fixed to the side of a tree and used by a lumberjack when working at some height from the ground.