On

1. (adj) In the state of being active, functioning or operating. 2. (adj) Happening; taking place; being or due to be put into action. 3. (adj) (informal) Of a person, used to express agreement to or acceptance of a proposal or challenge made by that person; most commonly with subject "you" (see you're on). 4. (adj) (postpositive) Of a stated part of something, oriented towards the viewer or other specified direction. 5. (adj) Fitted; covering or being worn. 6. (adv) To an operating state. 7. (adv) So as to cover or be fitted. 8. (adv) Along, forwards (continuing an action), onwards. 9. (adv) In continuation, at length. 10. (adj) (chiefly UK, informal, chiefly in the negative) Acceptable, appropriate. 11. (adj) (chiefly in the negative) Possible; capable of being successfully carried out. 12. (adj) (e.g. of points in a game) Available; remaining. 13. (adj) (baseball, informal) Having reached a base as a runner and being positioned there, awaiting further action from a subsequent batter. 14. (adj) (cricket) Within the half of the field on the same side as the batsman's legs; the left side for a right-handed batsman. 15. (adj) (snooker, postpositive) Of a ball, being the next in sequence to be potted, according to the rules of the game. 16. (adv) Of betting odds, denoting a better-than-even chance. See also odds-on. 17. (v) (Singapore, Philippines, Malaysia, Nigeria, transitive, colloquial) To switch on. 18. (adj) (informal, of a person) Performative or funny in a wearying manner. 19. (adj) (euphemistic) Menstruating. 20. (adv) (infrequent in the US) Later. 21. (adv) (snooker) Of a ball, into a pottable position. 22. (adj) (acting, drama, roleplaying games) Acting in character. 23. (n) In the Japanese language, a pronunciation, or reading, of a kanji character that was originally based on the character's pronunciation in Chinese, contrasted with kun. 24. (n) Synonym of Heliopolis (“ancient Egyptian city”). 25. (n) Abbreviation of Ontario: a province of Canada. [A province in eastern Canada. Capital: Toronto.] 26. (n) (linguistics) Initialism of Old Norse. [The language of Scandinavia until the 14th century, the common ancestor of modern Swedish, Danish, Norwegian, Faroese, and Icelandic.]