Safekeeping means protecting or guarding an object. You might put a batch of cupcakes on top of the refrigerator for safekeeping, hoping to keep them safe from your hungry roommates until after dinner.
The noun safekeeping almost always comes after the word "for," describing the way you protect something by putting it in a safe place. Voters' ballots might be held by an official for safekeeping until they're counted, and your friend might put your earrings in her pocket for safekeeping while you're at your swimming lesson. Safekeeping is sometimes spelled as two separate words, and it comes from the sense of keeping some object safe.