'Tuning fork' definitions:

Definition of 'tuning fork'

From: WordNet
noun
A metal implement with two prongs that gives a fixed tone when struck; used to tune musical instruments

Definition of 'Tuning fork'

From: GCIDE
  • Tuning \Tun"ing\ (t[=u]n"[i^]ng), a. & n. from Tune, v. [1913 Webster]
  • Tuning fork (Mus.), a steel instrument consisting of two prongs and a handle, which, being struck, gives a certain fixed tone. It is used for tuning instruments, or for ascertaining the pitch of tunes. [1913 Webster]