Source : Webster's Revised Unabridged Dictionary (1913)

Irrorate \Ir"ro*rate\, v. t. [imp. & p. p. {Irrorated}; p. pr. &
   vb. n. {Irrorating}.] [L. irroratus, p. p. of irrorare to
   bedew; pref. ir- in + ros, roris, dew.]
   To sprinkle or moisten with dew; to bedew. [Obs.]

Irrorate \Ir"ro*rate\, a. (Zo["o]l.)
   Covered with minute grains, appearing like fine sand.