Source : Webster's Revised Unabridged Dictionary (1913)

Altar \Al"tar\, n. [OE. alter, auter, autier, fr. L. altare, pl.
   altaria, altar, prob. fr. altus high: cf. OF. alter, autier,
   F. autel. Cf. {Altitude}.]
   1. A raised structure (as a square or oblong erection of
      stone or wood) on which sacrifices are offered or incense
      burned to a deity.

            Noah builded an altar unto the Lord.  --Gen. viii.
                                                  20.

   2. In the Christian church, a construction of stone, wood, or
      other material for the celebration of the Holy Eucharist;
      the communion table.

   Note: Altar is much used adjectively, or as the first part of
         a compound; as, altar bread or altar-bread.

   {Altar cloth} or

   {Altar-cloth}, the cover for an altar in a Christian church,
      usually richly embroidered.

   {Altar cushion}, a cushion laid upon the altar in a Christian
      church to support the service book.

   {Altar frontal}. See {Frontal}.

   {Altar rail}, the railing in front of the altar or communion
      table.

   {Altar screen}, a wall or partition built behind an altar to
      protect it from approach in the rear.

   {Altar tomb}, a tomb resembling an altar in shape, etc.

   {Family altar}, place of family devotions.

   {To lead (as a bride) to the altar}, to marry; -- said of a
      woman.

Source : WordNet®

altar
     n 1: the table in Christian churches where communion is given
          [syn: {communion table}, {Lord's table}]
     2: a raised structure on which gifts or sacrifices to a god are
        made