The Collaborative International Dictionary of English v.0.48:

Cilia \Cil"i*a\, n. pl. Cilium, the sing., is rarely used. [L.
   cilium eyelid.]
   1. (Anat.) The eyelashes.
      [1913 Webster]

   2. (Biol.) Small, generally microscopic, vibrating appendages
      lining certain organs, as the air passages of the higher
      animals, and in the lower animals often covering also the
      whole or a part of the exterior. They are also found on
      some vegetable organisms. In the Infusoria, and many
      larval forms, they are locomotive organs.
      [1913 Webster]

   3. (Bot.) Hairlike processes, commonly marginal and forming a
      fringe like the eyelash.
      [1913 Webster]

   4. (Zool.) Small, vibratory, swimming organs, somewhat
      resembling true cilia, as those of Ctenophora.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "cilia":
   Golgi apparatus, aster, basal body, cell membrane,
   central apparatus, central body, centriole, centroplasm,
   centrosome, centrosphere, chloroplast, chromoplast, cytocentrum,
   flagella, kinoplasm, microbody, microcentrum, mitochondrion, pili,
   plasmodesmata, plastid, plastosome, ribosome, spherosome,
   spindle fibers, vacuole