precipitate

First recorded in 1520–30; the verb and adjective derive from Latin praecipitātus (past participle of praecipitāre “to cast down headlong”), equivalent to praecipit- (stem of praeceps “steep”; see precipice) + -ātus past participle suffix (see -ate¹); the noun comes from New Latin praecipitātum “a precipitate,” noun use of neuter of praecipitātus

The verb precipitate comes from Latin praecipitāt-, the past participle stem of praecipitāre “to fall headlong, leap down, hurl or throw down, throw overboard,” a derivative of the adjective praeceps (stem praecipit- ) “falling headlong, impetuous (in action), advanced in age, declining, abrupt, sudden.” Praeceps is formed from the adverb, preposition, and prefix prae, prae- “in front, ahead” and -ceps (stem -cepit- ), a combining form of caput (stem capit- ) “head”; praeceps literally means “headfirst.”
The chemical sense of precipitate, “to separate (a substance) in solid form from a solution,” first appears in New Latin praecipitāre at the end of the 15th century, and is first recorded in English in the 17th century. The related meteorological sense “to fall to earth as rain, snow, hail, or drizzle” dates from the end of the 18th century.

C16: from Latin praecipitāre to throw down headlong, from praeceps headlong, steep, from prae before, in front + caput head