■ verb
1》 (of a structure) suddenly fall down or give way.
↘[usu. as adjective ~d ] (of a lung or blood vessel) fall inwards and become flat and empty.
2》 fall down as a result of illness or injury.
3》 fail suddenly and completely.
■ noun
1》 an instance of a structure collapsing.
2》 a sudden failure or breakdown.
Origin
C17: from medical L. collaps- , collabi , from col- 'together' + labi 'to slip'.