The Collaborative International Dictionary of English v.0.48:

Ration \Ra"tion\ (r[=a]"sh[u^]n or r[a^]sh"[u^]n), n. [F., fr.
   L. ratio a reckoning, calculation, relation, reference, LL.
   ratio ration. See Ratio.]
   1. A fixed daily allowance of provisions assigned to a
      soldier in the army, or a sailor in the navy, for his
      subsistence.
      [1913 Webster]

   Note: Officers have several rations, the number varying
         according to their rank or the number of their
         attendants.
         [1913 Webster]

   2. Hence, a certain portion or fixed amount dealt out; an
      allowance; an allotment.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ration \Ra"tion\, v. t.
   To supply with rations, as a regiment.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ration
    n 1: the food allowance for one day (especially for service
         personnel); "the rations should be nutritionally balanced"
    2: a fixed portion that is allotted (especially in times of
       scarcity)
    v 1: restrict the consumption of a relatively scarce commodity,
         as during war; "Bread was rationed during the siege of the
         city"
    2: distribute in rations, as in the army; "Cigarettes are
       rationed" [syn: ration, ration out]