[twic]

It may be more commonly used in British than in American, but even in British, i think it's less commonly used than 'triple'. For me, a native British speaker, the only things that are ever treble are twenties, whiskies, and clefs.

[toyg]

You must be upper-class. The only treble that working-class Brits know, is when you win the Premier League and two other cups in the same season.

[CalRobert]

"It may be more commonly used in British than in American"

What is this American you speak of? Perhaps it's the unique dialect of Spanish spoken in southern California? Or the Canadian French spoken in bits of northeastern North America? Or the dialect of English spoken in Belize?