nose-dive

The compound "nose-dive" originated in early 20th-century aviation slang, vividly describing an aircraft's steep, uncontrolled descent with its nose pointed directly downward. It literally combines "nose," the foremost projecting part, with "dive," meaning to plunge headlong. The term's logic is powerfully visual, equating the aircraft's front to a creature's nose plunging earthward. This concrete, technical imagery was soon adopted into general English to describe any sudden, drastic decline, whether in economics, quality, or morale, retaining its sense of a precipitous and often uncontrolled fall.

Structure: nose + dive - nose (Old English nosu): The projecting part of the face. In this compound, it functions as a metaphorical element suggesting a head-first or forward-plunging motion. - dive (Old English dȳfan): To plunge headfirst into water. In this compound, it functions as the core action, indicating a steep, rapid descent.