Source : Webster's Revised Unabridged Dictionary (1913)

Infiltrate \In*fil"trate\, v. i. [imp. & p. p. {Infiltrated}; p.
   pr. & vb. n. {Infiltrating}.] [Pref. in- + filtrate: cf. F,
   s'infiltrer. Cf. {Infilter}.]
   To enter by penetrating the pores or interstices of a
   substance; to filter into or through something.

         The water infiltrates through the porous rock.
                                                  --Addison.