(UK) The act of exempting someone from duty because of injury or ill health.

invalidity

plural of invaliding

(dated) An early wheelchair.

plural of invalid chair

(chiefly UK, history) A three-wheeled motor vehicle allowing disabled people to drive on the road, no longer used because of safety concerns.

plural of invalid carriage

simple past tense and past participle of invalid out

To leave or be excluded because of an injury or infirmity

The theater; stage productions generally.