To change climate to an appropriate level, see air conditioning.

To cause a certain response to a stimulus, see conditioning.

A status effect which is usually negative, see Condition (computer gaming).

A proposition upon which another proposition depends, such as "if-then" statements. See logical conditional.

Living condition, see Quality of life.

To replace moisture or oils, especially in hair, see conditioner.

A disease, such as a heart condition.

necessary condition, sufficient condition, necessary and sufficient condition