The Collaborative International Dictionary of English v.0.48:

Pyoid \Py"oid\, a. [Gr. ? pus + --oid.] (Med.)
   Of or pertaining to pus; of the nature of, or like, pus.
   [1913 Webster]

   Pyoid corpuscles (Med.), cells of a size larger than pus
      corpuscles, containing two or more of the latter.
      [1913 Webster]