Source : Webster's Revised Unabridged Dictionary (1913)

Tardigrade \Tar"di*grade\, n. (Zo["o]l.)
   One of the Tardigrada.

Tardigrade \Tar"di*grade\, a. [L. tardigradus; tardus slow +
   gradi to step: cf. F. tardigrade.]
   1. Moving or stepping slowly; slow-paced. [R.] --G. Eliot.

   2. (Zo["o]l.) Of or pertaining to the Tardigrada.

Source : WordNet®

tardigrade
     n : an arthropod of the division Tardigrada