(at, unstressed ət) prep.
1. In the exact position of: the point at the center of the circle.
2. On or near the coming of: the train leaving at two; a man at sixty.
3. During the course or lapse of: At the moment the matter is uncertain.
4. In contact with; on; upon: at the bottom of the sea.
5. To or toward: Look at that sunset!
6. Through; by way of: smoke coming out at the windows.
7. Within the limits of; present in: to be at the ball grounds.
8. Engaged or occupied in: to be at work.
9. Attending: He was at the party.
10. In the state or condition of: a nation at war.
11. In the region or vicinity of; in proximity to: The car is at the door.
12. Viewed from; with an interval of: a target at sixty paces.
13. Having reference to: He winced at the thought.
14. In the manner of: at a trot.
15. In pursuit or quest of; in the direction of: to catch at straws.
16. Dependent upon: to be at an enemy's mercy.
>17 According to: Proceed at your discretion.
18. To the extent of; amounting to: paying interest at two per cent; pencils at a dime apiece. [OE æt] Synonyms: about, by, during, in, near, on, to, toward, with, within. As regards place, at is not used with names of countries; we say in England, in France, etc.; with names of cities and towns we use at when we think merely of the local or geographical point; when we think of inclusive space, we employ in; as, we arrived at Liverpool; there are few rich men in this village. As regards time, at is used of a point of time, as of the hour, minute, or second; as, the train leaves at 10:30 a.m.; at is also used of indefinite divisions of time involving some duration; as, at morning, noon, or night; to lie awake at night. We say at the hour, on the day, in the year. On with certain divisions of time has a special precision, signifying exactly at, neither before nor after; as, the train leaves on the hour.

Chem. Astatine (symbol At).

Assimilated var. of AD-.