The tennis slang term for winning a set 6-0 is a bagel. The term "bagel" refers to the shape of the number 0, which resembles a bagel. When a player wins a set 6-0, it is colloquially referred to as a "bagel" due to the 0 score.
An even rarer occurrence is a "golden set", where a player wins a set without dropping a single point. This is an extremely uncommon feat in professional tennis.