1 A premise upon which the fulfillment of an agreement depends; stipulation.
2. A provision making the effect of a legal instrument contingent upon an uncertain event; also; the event itself.
3. Something essential to the appearance or occurrence of something else; prerequisite: as an environmental requirement; the subordinate clause of a conditional sentence.
4. A restricting or modifying factor; qualification.
5. An unsatisfactory academic grade that may be raised by doing additional work.
6. A state of being.
7. Social status; rank; a usually defective state of health.
8. A state of physical fitness or readiness for use.

The state of an expression or a variable (for example, when a result can be either true or false, or equal or not equal).

ETYM Cf. Late Lat. conditionare. Related to Condition.
1. To apply conditioner to in order to make smooth and shiny; of hair.
2. To establish a conditioned response (behaviorism).
3. To put into a better state.