The Collaborative International Dictionary of English v.0.48:

Alms \Alms\ ([add]mz), n. sing. & pl. [OE. almes, almesse, AS.
   [ae]lmysse, fr. L. eleemosyna, Gr. 'elehmosy`nh mercy,
   charity, alms, fr. 'eleei^n to pity. Cf. Almonry,
   Eleemosynary.]
   Anything given gratuitously to relieve the poor, as money,
   food, or clothing; a gift of charity.
   [1913 Webster]

         A devout man . . . which gave much alms to the people.
                                                  --Acts x. 2.
   [1913 Webster]

         Alms are but the vehicles of prayer.     --Dryden.
   [1913 Webster]

   Tenure by free alms. See Frankalmoign. --Blackstone.
      [1913 Webster]

   Note: This word alms is singular in its form (almesse), and
         is sometimes so used; as, "asked an alms." --Acts iii.
         3. "Received an alms." --Shak. It is now, however,
         commonly a collective or plural noun. It is much used
         in composition, as almsgiver, almsgiving, alms bag,
         alms chest, etc.
         [1913 Webster]

WordNet (r) 3.0 (2006):

alms
    n 1: money or goods contributed to the poor

Easton's 1897 Bible Dictionary:

Alms
   Not found in the Old Testament, but repeatedly in the New. The
   Mosaic legislation (Lev. 25:35; Deut. 15:7) tended to promote a
   spirit of charity, and to prevent the occurrence of destitution
   among the people. Such passages as these, Ps. 41:1; 112:9; Prov.
   14:31; Isa. 10:2; Amos 2:7; Jer. 5:28; Ezek. 22:29, would also
   naturally foster the same benevolent spirit.

     In the time of our Lord begging was common (Mark 10:46; Acts
   3:2). The Pharisees were very ostentatious in their almsgivings
   (Matt. 6:2). The spirit by which the Christian ought to be
   actuated in this duty is set forth in 1 John 3:17. A regard to
   the state of the poor and needy is enjoined as a Christian duty
   (Luke 3:11; 6:30; Matt. 6:1; Acts 9:36; 10:2, 4), a duty which
   was not neglected by the early Christians (Luke 14:13; Acts
   20:35; Gal. 2:10; Rom. 15:25-27; 1 Cor. 16:1-4). They cared not
   only for the poor among themselves, but contributed also to the
   necessities of those at a distance (Acts 11:29; 24:17; 2 Cor.
   9:12). Our Lord and his attendants showed an example also in
   this (John 13:29).

     In modern times the "poor-laws" have introduced an element
   which modifies considerably the form in which we may discharge
   this Christian duty.


Bouvier's Law Dictionary, Revised 6th Ed (1856):

ALMS. In its most extensive sense, this comprehends every species of relief
bestowed upon the poor, and, therefore, including all charities. In a more,
limited sense, it signifies what is given by public authority for the relief
of the poor. Shelford on Mortmain, 802, note (x); 1 Dougl. Election Cas.
370; 2 Id. 107; Heywood on Elections, 263.