(dated) Alternative spelling of oneself

The number 100.

Used in a common chronometric counting scheme, in which each iteration is sequentially numbered and supposed to be approximately one second in length.

The number 1000.

The cardinal number immediately following thirty and before thirty-two; thirty plus one.

The cardinal number occurring after twenty and before twenty-two, represented in Roman numerals as XXI and in Arabic numerals as 21.

(card games) Blackjack. / (sports) A basketball-based game in which players attempt to score exactly twenty-one points.

(US) One thousand plus one.

The cardinal number following eighty and preceding eighty-two.

None at all.