1732, "fall together, fall into an irregular mass through loss of support or rigidity," from Latin collapsus, past participle of collabi "fall together," from assimilated form of com "with, together" (see com-) + labi "to fall, slip" (see lapse (n.)).
Figurative sense of "come to nothing, fail" is from 1801. Transitive sense "cause to collapse" is from 1883. The adjective collapsed is attested from c. 1600, originally of groups of persons, "fallen from a spiritual or religious state," perhaps from co- + lapsed. Related: Collapsing.
c. 1600, "exact correspondence in substance or nature," from French coincidence, from coincider, from Medieval Latin coincidere, literally "to fall upon together," from assimilated form of Latin com "with, together" (see com-) + incidere "to fall upon" (from in- "upon" + combining form of cadere "to fall," from PIE root *kad- "to fall").
From 1640s as "occurrence or existence during the same time." Meaning "a concurrence of events with no apparent connection, accidental or incidental agreement" is from 1680s, perhaps first in writings of Sir Thomas Browne.
"to fall or fall into with a sound like 'plop,' " 1821, imitative of the sound of a smooth object dropping into water. Related: Plopped; plopping. Thackary (mid-19c.) used plap (v.). As a noun from 1833.
1680s, with reference to leaves, petals, teeth, etc., "falling off at a certain stage of existence," from Latin deciduus "that which falls down," from decidere "to fall off, fall down," from de "down" (see de-) + combining form of cadere "to fall," from PIE root *kad- "to fall." Of trees and bushes, "losing foliage every year" (opposed to evergreen), from 1778. The Latin adjective was used of shooting stars and testicles, but it seems not to have been used of trees or leaves (the phenomenon in Italy seems to be restricted to the mountain regions). Related: Deciduousness.
1705, "be identical in substance or nature;" 1715, "occupy the same space, agree in position," from Medieval Latin coincidere (used in astrology), literally "to fall upon together," from assimilated form of Latin com "with, together" (see com-) + incidere "to fall upon" (from in- "upon" + combining form of cadere "to fall," from PIE root *kad- "to fall"). From 1809 as "occur at the same time." Related: Coincided; coinciding. Latin coincidere was used as a verb in English from 1640s.
It forms all or part of: accident; cadaver; cadence; caducous; cascade; case (n.1); casual; casualty; casuist; casus belli; chance; cheat; chute (n.1); coincide; decadence; decay; deciduous; escheat; incident; occasion; occident; recidivist.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit sad- "to fall down;" Latin casus "a chance, occasion, opportunity; accident, mishap," literally "a falling," cadere "to fall, sink, settle down, decline, perish;" Armenian chacnum "to fall, become low;" perhaps also Middle Irish casar "hail, lightning."
1540s, transitive, "shed in small drops;" 1560s, intransitive, "fall in very fine particles, as water from the clouds," of uncertain origin. Perhaps it is an alteration of drysning "a falling of dew" (c. 1400), from Old English -drysnian, which is related to dreosan "to fall" (see dreary). Or perhaps it is a frequentative of Middle English dresen "to fall," from Old English dreosan. Related: Drizzled; drizzling.
As a noun, "a light rain, mist," from 1550s.