To suspend (a parliamentary session) or to discontinue the meetings of (an assembly, parliament etc.) without formally ending the session.
In social interactions, to request a deferral of an invitation. To "take a rain check" is a polite way to turn down an engagement, usually with the implication that one is simply postponing it and another time might be acceptable.
To request or accept a rain check (an agreement from a merchant to honor a special offer, temporarily unavailable, after the expiration date).