1. in a position above, but in contact with and supported by; upon
2. in contact with (any surface); covering or attached to
3. so as to be supported by leaning on his elbow
4. in the surface of a scar on the body
5. 1. near to; by a cottage on the lake, seated on my right
   2. having as its location a house on Main Street
   3. assigned to work at or in on the maternity ward, on the switchboard
6. at or during the time of on entering, on the first day
7. having a basis of or having its ground in (something specified) based on her diary, on purpose
8. connected with as a part or member on the faculty
9. engaged in on a trip
10. in the state or condition of on parole, on fire
11. in a (specified) manner: chiefly archaic except in phrases with the on the sly
12. as a result of a profit on the sale
13. in the direction or vicinity of light shone on us
14. so as to affect to put a curse on someone
15. regularly following (a regimen), ingesting (medicine), etc., as to promote good health on a diet, on penicillin
16. 1. through the means or use of to live on bread, running on diesel fuel
    2. through the medium of on the phone, to act on TV
    3. using for transportation on a train
17. with regard to; concerning an essay on war
18. coming after: used to indicate repetition we suffered insult on insult
19. placing obligation or responsibility with rely on me; the onus is on him
20. onto just throw it on the porch
21. ☆ chargeable to; at the expense of have a drink on the house; lunch is on me
22. in jazz, popular music, etc.,
    1. playing Jim is on guitar
    2. in () he played on the Basie band
23. ☆ Informal habitually using; addicted to to be on drugs
24. Informal carried by I have no money on me
25. Informal constantly nagging at, finding fault with, etc. the boss has been on him all day
26. 1. Dialectal of, at, about, for, in
    2. Brit. in (, , )
    3. Chiefly Northeast in () waiting on line at the bank

Etymology: ME < OE on, an, akin to Ger an, Goth ana, ON ā < IE base *an, *anō, prob. meaning “obliquely toward, slanting toward” > Gr ana

adverb

1. in or into a situation or position of contacting, being supported by, or covering put your shoes on
2. in a direction to or toward he looked on
3. 1. in advance; forward; ahead move on
   2. Brit. along in time; later; after thirty years on, nothing had changed
4. lastingly; continuously she sang on
5. into operation, performance, or action switch on the light
6. Baseball on base
7. Theater on stage

adjective

1. in action, operation, or occurrence the TV is on
2. near or nearer
3. arranged or planned for tomorrow's game is still on
4. Slang performing or functioning at a high level of competence he was really on in last night's game
5. Cricket designating that side of the field, or of the wicket, where the batsman stands

noun

1. the fact or state of being on
2. Cricket the on side