breakdown · noun C /ˈbreɪk.daʊn/Full view
breakdown (ILLNESS)
B2 a short period of mental illness when people are too ill to continue with their normal lives
Dictionary examples:

Later that year she had a breakdown.

a nervous breakdown

Learner example:

Instead of that I almost end[ed] up in hospital suffering [a] nervous breakdown. (First Certificate in English; B2; Greek)

breakdown (NOT WORKING)
B2 when a vehicle or machine stops working for a period of time
Dictionary example:

I had a breakdown in the middle of the road.

Learner example:

On Friday we went to Scotland but unfortunately we had a breakdown. By chance a very nice farmer fixed our car and [as] it was late he suggested we should spend the night on his farm. (First Certificate in English; B2; French)

breakdown (FAILURE)
C1 when something such as communication or a relationship fails or ends
Dictionary example:

a breakdown in the peace talks

Learner example:

Eventually, society may be affected by the breakdown of these relationships. (International English Language Testing System; C1; Tagalog)

breakdown (EXPLANATION)
C2 a short explanation of the details of something
Dictionary example:

I need a breakdown of the costs involved.

Learner example:

The pie charts showing the breakdown of annual spending of the school take into account money spent on insurance, teachers' salaries, furniture and equipment, resources (such as books), and other workers' salaries. (International English Language Testing System; C2; Hungarian)

Cambridge University Press