NOSEDIVE
dive, nose dive, nosedive
(noun) a steep nose-down descent by an aircraft
nosedive
(noun) a sudden sharp drop or rapid decline; “the stock took a nosedive”
nosedive
(verb) plunge nose first; drop with the nose or front first, of aircraft
Source: WordNet® 3.1
Etymology
Noun
nosedive (plural nosedives)
A headfirst fall or jump.
(economics) A rapid fall in price or value.
Verb
nosedive (third-person singular simple present nosedives, present participle nosediving, simple past and past participle nosedived)
(intransitive, of aircraft) To dive down in a steep angle.
(intransitive, economy) To perform a rapid fall in price or value.
Source: Wiktionary