collapses; collapsed; collapsing
1
: to break apart and fall down suddenly
The bridge/building collapsed.
The roof collapsed under a heavy load of snow.
The chair he was sitting in collapsed.
2
a
: to fall down or become unconscious because you are sick or exhausted
He collapsed on stage during the performance and had to be rushed to the hospital.
b
: to completely relax the muscles of your body because you are very tired, upset, etc.
She came home from work and collapsed on the sofa.
The crying child ran to his mother and collapsed in her arms.
3
a
: to fail or stop working suddenly : to break down completely
The civilization collapsed for reasons that are still unknown.
He warned that such measures could cause the economy to collapse.
Negotiations have completely collapsed.
b
: to lose almost all worth : to become much less valuable
The country's currency collapsed.
Oil prices had collapsed.
4
medical
: to become flat and empty
a blood vessel that collapsed
a collapsed lung
5
: to fold together
The stroller collapses easily.
You can collapse the stroller easily and store it in the trunk of your car.
plural collapses
1
: a situation or occurrence in which something (such as a bridge, building, etc.) suddenly breaks apart and falls down
—usually singular
a fatal bridge collapse
The earthquake caused the collapse of several homes.
the collapse of the roof
The structure is in danger of collapse.
2
: a situation or occurrence in which someone suddenly falls down or becomes unconscious because of being sick or exhausted
—usually singular
After her collapse she was rushed to the hospital.
He suffered a collapse at work.
She was on the verge of collapse.
3
: a situation or occurrence in which something (such as a system or organization) suddenly fails : a complete failure or breakdown
—usually singular
the collapse of the Soviet Union
the collapse of negotiations
She moved to the city after the collapse of her marriage.
The country has endured civil war and economic collapse.
4
: a situation or occurrence in which something loses almost all of its worth or value
The country's currency is in danger of collapse.
—usually singulara collapse in the value of their currency
Cite this Entry
“Collapse.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/collapse. Accessed 16 Apr. 2026.
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