to fall or cave in; crumble suddenly

The roof collapsed and buried the crowd.

to be made so that sections or parts can be folded up, as for convenient storage

This bridge table collapses.

to break down; come to nothing; fail

Despite all their efforts the peace talks collapsed.

to fall unconscious or as if unconscious or physically depleted, as from a stroke, heart attack, disease, or exhaustion.

Pathology .

to sink into extreme weakness.

(of lungs) to come into an airless state.

to cause to collapse

He collapsed the table easily.

a falling in or together

Three miners were trapped by the collapse of the tunnel roof.

a sudden, complete failure; breakdown

The bribery scandal brought about the complete collapse of his industrial empire.