at

At is used to show position, to show something that an action refers to, or to show a condition or something that is happening. (preposition)

Attending a movie is an example of being at a movie.
Pointing a bow and arrow towards a target is an example of pointing at a target.
When troops are commanded to no longer stand in attention that is an example of being commanded to stand at ease.

See at in Webster's New World College Dictionary

on; in; near; by: at is the preposition of general (usually static) location, and is replaced by in, on, etc. when a more precise indication of location is needed: at the office, at the edge of town
1. to or toward as the goal or object: look at her, swing at the ball, don't shout at me
2. criticizing, attacking, pestering, etc.: the critics are at him again
through: come in at the front door
from: get the facts at their source
attending: at the party
occupied in; busy with: at work
in a condition or state of: at war
in the manner of: at a trot
because of; in response to: terrified at the sight, to smile at a remark
according to: at his discretion
with reference to: good at tennis
in the amount or number, to the degree, for the price, etc. of: at twenty miles per hour, at five cents each
from an interval or distance of: visible at half a mile, at arm's length
1. occurring on the hour, minute, etc. of: at five fifteen
2. being of the age of: at sixty-five
during the period of: it happened at night

noun pl. at

a monetary unit of Laos, equal to of a kip

astatine

See at in American Heritage Dictionary 4

(ăt; ət when unstressed)

preposition

a. In or near the area occupied by; in or near the location of: at the market; at our destination.
b. In or near the position of: always at my side; at the center of the page.
To or toward the direction or location of, especially for a specific purpose: Questions came at us from all sides.
Present during; attending: at the dance.
Within the interval or span of: at the dinner hour; at a glance.
In the state or condition of: at peace with one's conscience.
In the activity or field of: skilled at playing chess; good at math.
To or using the rate, extent, or amount of; to the point of: at 30 cents a pound; at high speed; at 20 paces; at 350°F.
On, near, or by the time or age of: at three o'clock; at 72 years of age.
On account of; because of: rejoice at a victory.
By way of; through: exited at the rear gate.
In accord with; following: at my request.
Dependent upon: at the mercy of the court.
Occupied with: at work.