The Collaborative International Dictionary of English v.0.48:

Alveolate \Al"ve*o*late\, a. [L. alveolatus, fr. alveolus.]
   (Bot.)
   Deeply pitted, like a honeycomb.
   [1913 Webster]

WordNet (r) 3.0 (2006):

alveolate
    adj 1: pitted with cell-like cavities (as a honeycomb) [syn:
           alveolate, faveolate, cavitied, honeycombed,
           pitted]