(on, ôn) prep.
1. In contact with the upper surface of; above and supported by: lying on the ground.
2. In contact with any surface or part of: a blow on the head.
3. So as to be suspended from: a puppet on a string.
4. Directed or moving along the course of: Be on your way.
5. Near; adjacent to: the town on the river bank; the store on your right.
6. Within the duration of: He arrived on my birthday.
7. At the moment or point of: on the hour; at the time of: He withdrew on my speaking thus.
8. In a state or condition of: on fire; on record.
9. By means of; with the support of: on wheels; on all fours.
10. Using as a means of sustenance, activity, etc.: living on fruit.
11. Accumulated with; in addition to: thousands on thousands of them.
12. Sustained or confirmed by; with the authority of: committed on purpose; I swear to it on my honor.
13. In the interest or favor of: betting on a horse.
14. Concerning; about: a work on economics.
15. Engaged in; occupied or connected with: on a journey; on duty all night.
16. As a consequence or result of: making a profit on tips.
17. In accordance with or relation to; in terms of: measured on the Centigrade scale.
18. Directed, tending, or moving toward or against: making war on the enemy.
19. Following after: disease on the heels of famine.
20. Colloq. With; accompanying, as about one's person: Do you have five dollars on you?
21. Colloq. At the expense of; paid by: The joke is on them; drinks on the house. See synonyms under ABOVE, AT.
—to have something on U.S. Colloq. To have knowledge, possess evidence, etc., against (a person).
—adverb
1. In or into a position or condition of contact, adherence, covering, etc.: He put his hat on.
2. In the direction of something: He looked on while they played.
3. In advance; ahead, in space or time: a collision head on; later on.
4. In continuous course or succession: The music went on.
5. In or into operation, performance, or existence: to turn the electricity on.
—and so on And like what has gone before; et cetera.
—on and on Without interruption; continuously.
—to be on to To be aware of or informed about (someone, something, etc.); understand.
—adjective
1. In operation, progress, or application: The play is on; The brake is on.
2. Near; located nearer.
3. In cricket, indicating or pertaining to the side of the wicket and field where the batsman stands.
—noun
1. The state or fact of being on.
2. In cricket, the on side of the field or wicket. [OE on, an]

(on)
The Egyptian name for HELIOPOLIS.