To put aside, to not act on (proposals, suggestions, advice).
To categorize; especially to limit or be limited to a particular category, role, etc.
A category.
One of an array of compartments for housing pigeons.
One of an array of compartments for receiving mail and other messages at a college, office, etc.
One of an array of compartments for storing scrolls at a library.
A similar compartment in a desk, used for sorting and storing papers.
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).