<p><strong>noun</strong></p><ul><li>a plunge of an aircraft with the forward part pointing downward.</li><li>a sudden sharp drop or rapid decline: a time when market values were in a nosedive.</li></ul><p><strong>verb</strong></p><ul><li>(used without object), nose·dived or nose·dove, nose·dived, nose·div·ing.<ul><li>to go into a nosedive: a warning that prices might nosedive.</li></ul></li></ul>