Meaning

noun a sudden unforeseen crisis (usually involving danger) that requires immediate action

noun a state in which martial law applies

noun a brake operated by hand; usually operates by mechanical linkage

originBorrowed from Medieval Latin emergentia, from Latin emergens, present participle of emergo (“to emerge, arise, come forth”), equivalent to emergent + -cy or emerge + -ency. Doublet of emergence.

Etymology from Wiktionary, CC BY-SA 3.0