(n.) a party attended by naked dancers
A long-lost term from nineteenth century slang, a buff-ball was a dance party at which everybody was naked. Those Victorians really knew how to have a good time.
But a question: why is being naked known as being in the buff?
As a term for nakedness, in the buff is actually a lot older than it might seem: it dates way back to the mid seventeenth century (although Elizabethan playwright Thomas Dekker alluded to being in “buff-skin” even earlier than that). Oddly, in this context buff comes from the same root as buffalo. In English, buffalos were originally known as buffles way back in the early sixteenth century, before the word buffalo was adopted into English (probably from Portuguese) in the late 1500s.
Buff was merely a shortened form of buffle that emerged in the mid 1500s, before people began making and talking about buff-leather in 1570s. It was in reference to the buffalo’s bare, tanned skin or “buff-leather” hide that the word buff first began to be used colloquially as another word for nakedness around the early 1600s—and we’ve been talking about being in the buff ever since.