'nosedive' definitions:

Definition of 'nosedive'

From: WordNet
noun
A sudden sharp drop or rapid decline; "the stock took a nosedive"
noun
A steep nose-down descent by an aircraft [syn: dive, nose dive, nosedive]
verb
Plunge nose first; drop with the nose or front first, of aircraft

Definition of 'nosedive'

From: GCIDE
  • nosedive \nose"dive`\, nose-dive \nose"-dive`\v. i. To drop with the nose or front first, as of an airplane.
  • Syn: nosedive. [WordNet 1.5]