The Collaborative International Dictionary of English v.0.48:

Leguminous \Le*gu"mi*nous\ (-m[i^]*n[u^]s), a. [Cf. F.
   l['e]gumineux.]
   1. Pertaining to pulse; consisting of pulse.
      [1913 Webster]

   2. (Bot.) Belonging to, or resembling, a very large natural
      order of plants (Leguminos[ae]), which bear legumes,
      including peas, beans, clover, locust trees, acacias, and
      mimosas.
      [1913 Webster]

WordNet (r) 3.0 (2006):

leguminous
    adj 1: relating to or consisting of legumes