\At\, prep. [AS. [ae]t; akin to OHG. az, Goth., OS., & Icel.
at, Sw. [*a]t, Dan. & L. ad.]
Primarily, this word expresses the relations of presence,
nearness in place or time, or direction toward; as, at the
ninth hour; at the house; to aim at a mark. It is less
definite than in or on; at the house may be in or near the
house. From this original import are derived all the various
uses of at. It expresses:
1. A relation of proximity to, or of presence in or on,
   something; as, at the door; at your shop; at home; at
   school; at hand; at sea and on land.
2. The relation of some state or condition; as, at war; at
   peace; at ease; at your service; at fault; at liberty; at
   risk; at disadvantage.
3. The relation of some employment or action; occupied with;
   as, at engraving; at husbandry; at play; at work; at meat
   (eating); except at puns.
4. The relation of a point or position in a series, or of
   degree, rate, or value; as, with the thermometer at
   80[deg]; goods sold at a cheap price; a country estimated
   at 10,000 square miles; life is short at the longest.
5. The relations of time, age, or order; as, at ten o'clock;
   at twenty-one; at once; at first.
6. The relations of source, occasion, reason, consequence, or
   effect; as, at the sight; at this news; merry at anything;
   at this declaration; at his command; to demand, require,
   receive, deserve, endure at your hands.
7. Relation of direction toward an object or end; as, look at
   it; to point at one; to aim at a mark; to throw, strike,
   shoot, wink, mock, laugh at any one.
{At all}, {At home}, {At large}, {At last}, {At length}, {At
once}, etc. See under {All}, {Home}, {Large}, {Last} (phrase
   and syn.), {Length}, {Once}, etc.
{At it}, busily or actively engaged.
{At least}. See {Least} and {However}.
{At one}. See {At one}, in the Vocabulary.
Syn: {In}, {At}.
Usage: When reference to the interior of any place is made
       prominent in is used. It is used before the names of
       countries and cities (esp. large cities); as, we live
       in America, in New York, in the South. At is commonly
       employed before names of houses, institutions,
       villages, and small places; as, Milton was educated at
       Christ's College; money taken in at the Customhouse; I
       saw him at the jeweler's; we live at Beachville. At
       may be used before the name of a city when it is
       regarded as a mere point of locality. ``An English
       king was crowned at Paris.'' --Macaulay. ``Jean
       Jacques Rousseau was born at Geneva, June, 28, 1712.''
       --J. Morley. In regard to time, we say at the hour, on
       the day, in the year; as, at 9 o'clock, on the morning
       of July 5th, in the year 1775.