Third-person singular simple present indicative form of costume.(verb)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "costumes" in a sentence
"Of the bathing at Trouville, a book might be written on the costumes alone -- on the suits of motley, the harlequins, the mephistopheles, the spiders, the 'grasshoppers green,' and the other eccentric _costumes de bain_ -- culminating in a lady's dress trimmed with death's heads, and a gentleman's, of an indescribable colour, after the pattern of a trail of seaweed."
"One thing about getting dressed up in costumes is that gender bending becomes normal."
"Trust me, we were making fun of those Batman and Robin costumes from the get go."