Source : Webster's Revised Unabridged Dictionary (1913)

Cribellum \Cri*bel"lum\ (kr?b?l"l?m), n. [L., a small sieve,
   dim. of cribrum sieve.] (Zo["o]l.)
   A peculiar perforated organ of certain spiders
   ({Ciniflonid[ae]}), used for spinning a special kind of silk.