O's

noun pl. O's, o's

1. the fifteenth letter of the English alphabet: from the Greek omega and omicron, both borrowed from the Phoenician
2. any of the speech sounds that this letter represents, as, in English, the vowel (ō) of boat, (ä) of hot, or (ô) of wrong
3. a type or impression for o or O
4. the fifteenth in a sequence or group
5. an object shaped like

adjective

1. of o or O
2. fifteenth in a sequence or group
3. shaped like ; circular or oval in shape