NOUN (3)

1. a prescribed number;
- Example: "all the salesmen met their quota for the month"

2. a proportional share assigned to each participant;

3. a limitation on imports;
- Example: "the quota for Japanese imports was negotiated"

The Collaborative International Dictionary of English v.0.48:

Quota \Quo"ta\ (kw[=o]"t[.a]), n. [LL., fr. L. quota (sc. pars),
   fr. quotus which or what in number, of what number, how many,
   fr. quot how many, akin to quis, qui, who: cf. It. quota a
   share. See Who.]
   1. A proportional part or share; the share or proportion
      assigned to each in a division. "Quota of troops and
      money." --Motley.
      [1913 Webster]

   2. a share of effort required to be performed, or a share of
      resources required to be contributed to some common
      purpose.
      [PJC]

WordNet (r) 3.0 (2006):

quota
    n 1: a prescribed number; "all the salesmen met their quota for
         the month"
    2: a proportional share assigned to each participant
    3: a limitation on imports; "the quota for Japanese imports was
       negotiated"