The Oxford Thesaurus An A-Z Dictionary of Synonyms - cap n.

1) hat, head covering: The plumber took off his cap and scratched his head. 2) lid, top, cover: Screw the cap on tight. 3) cap in hand. humbly, meekly, servilely, submissively, subserviently, docilely, respectfully: He went cap in hand to ask for a pay rise. --v. 4) surpass, outdo, outstrip, better, beat, exceed, top, excel: Betty capped her earlier triumphs by winning the semifinals. 5) cover, protect: As it's begun to rain, you'd best cap the camera lens.