's definition is - is. How to use 's in a sentence. used to form the possessive of singular nouns boy's, of plural nouns not ending in s children's, of some pronouns anyone's, and of word groups functioning as nouns the man in the corner's hat or pronouns someone else's Find the latest Sprint Corporation (S) stock quote, history, news and other vital information to help you with your stock trading and investing. S 1 1. The symbol for sulfur. 2. The symbol for entropy. S 2 abbr. 1. Football safety 2. Bible Samuel 3. satisfactory 4. Saturday 5. Sports shot 6. siemens 7. small 8. soprano 9. a. south b. southern 10. Baseball strike 11. Sports striker 12. Sunday s 1 or S (ĕs) n. pl. s's or S's also ss or Ss 1. The 19th letter of the modern English alphabet. 2. Any