Real Dictionary

precondition
countable noun: If one thing is a precondition for another, it must happen or be done before the second thing can happen or exist.

precondition in American English
a condition required beforehand if something else is to occur, be done, etc.
to prepare (someone or something) to behave, react, etc. in a certain way under certain conditions
noun: something that must come before or is necessary to a subsequent result; condition
transitive verb: to subject (a person or thing) to a special treatment in preparation for a subsequent experience, process, test, etc

precondition in British English
noun: a necessary or required condition; prerequisite
verb: to present successively two stimuli to (an organism) without reinforcement so that they become associated; if a response is then conditioned to the second stimulus on its own, the same response will be evoked by the first stimulus