A semi-formal dance for which girls get far too dressed up (gowns and fancy jewelry, etc.) and for which many guys come severely under-dressed. Humiliating, yes. Enjoyable, perhaps if you come drunk.
"Dude, did you see that girl's dress at cotillion? she swears she's at a prom?"
"Yeah man, all I wore was some khaki's and my dad's dress shirt."
A traditional filipino celebration similar to a quinceañera
, but for a girl's 18th and a boy's 21st birthdays. Girls are usually the ones who make a big deal out of it. It's not a required thing, but girls with rich or semi-rich families will usually over-do these celebrations and make their cotillion look like a wedding and have videos and pictures of the celebration on social websites, only to get ridiculed by the cost and the amount of seriousness those said girls put into their cotillion.
Girl 1: "Check out my cotillion!"
Girl 2: "Omg this is for your 18th birthday? I didn't even get a cake for my birthday."
Girl 1: "FOR YOUR INFORMATION It's a filipino tradition."
Girl 2: "Okay spoiled girl..."
A dance only dumb people go to.
Abbey: Ooh let's go to my Cotillion!
Me: YOU'RE A DUMB IDIOT
Abbey: What's that?