Source : Webster's Revised Unabridged Dictionary (1913)

At \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.

Home \Home\ (110), n. [OE. hom, ham, AS. h[=a]m; akin to OS.
   hem, D. & G. heim, Sw. hem, Dan. hiem, Icel. heimr abode,
   world, heima home, Goth. haims village, Lith. k["e]mas, and
   perh. to Gr.? village, or to E. hind a peasant; cf. Skr.
   ksh?ma abode, place of rest, security, kshi to dwell. ?, ? ]
   1. One's own dwelling place; the house in which one lives;
      esp., the house in which one lives with his family; the
      habitual abode of one's family; also, one's birthplace.

            The disciples went away again to their own home.
                                                  --John xx. 10.

            Home is the sacred refuge of our life. --Dryden.

            Home! home! sweet, sweet home! There's no place like
            home.                                 --Payne.

   2. One's native land; the place or country in which one
      dwells; the place where one's ancestors dwell or dwelt.
      ``Our old home [England].'' --Hawthorne.

   3. The abiding place of the affections, especially of the
      domestic affections.

            He entered in his house -- his home no more, For
            without hearts there is no home.      --Byron.

   4. The locality where a thing is usually found, or was first
      found, or where it is naturally abundant; habitat; seat;
      as, the home of the pine.

            Her eyes are homes of silent prayer.  --Tennyson.

            Flandria, by plenty made the home of war. --Prior.

   5. A place of refuge and rest; an asylum; as, a home for
      outcasts; a home for the blind; hence, esp., the grave;
      the final rest; also, the native and eternal dwelling
      place of the soul.

            Man goeth to his long home, and the mourners go
            about the streets.                    --Eccl. xii.
                                                  5.

   6. (Baseball) The home base; he started for home.

   {At home}.
      (a) At one's own house, or lodgings.
      (b) In one's own town or country; as, peace abroad and at
          home.
      (c) Prepared to receive callers.

   {Home department}, the department of executive
      administration, by which the internal affairs of a country
      are managed. [Eng.]

   {To be at home on any subject}, to be conversant or familiar
      with it.

   {To feel at home}, to be at one's ease.

   {To make one's self at home}, to conduct one's self with as
      much freedom as if at home.

   Syn: Tenement; house; dwelling; abode; domicile.

Source : WordNet®

at home
     n : a reception held in your own home
     adv : on the home team's field; "they played at home last night"