The Collaborative International Dictionary of English v.0.48:

lyophilized \lyophilized\ adj.
   dried by freezing and subsequent evaporation of the water in
   a high vacuum; -- used of tissue or blood or serum or other
   biological or sensitive substances.

   Syn: lyophilised, freeze-dried.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

lyophilized
    adj 1: used of tissue or blood or serum or other biological
           substances; dried by freezing in a high vacuum [syn:
           lyophilized, lyophilised, freeze-dried]