verb

(of a structure) suddenly fall down or give way.

the roof collapsed on top of me

cave in,fall in,subside,fall down,sag,slump,settle,give,give way,crumble,crumple,disintegrate,fall to pieces,come apart

noun

an instance of a structure falling down or giving way.

the collapse of a railway bridge

cave-in,giving way,subsidence,crumbling,disintegration