Source : Webster's Revised Unabridged Dictionary (1913)

Filiform \Fil"i*form\, a. [L. filum thread + -form: cf. F.
   filiforme.]
   Having the shape of a thread or filament; as, the filiform
   papill[ae] of the tongue; a filiform style or peduncle. See
   Illust. of {Antenn[AE]}.

Source : WordNet®

filiform
     adj : thin in diameter; resembling a thread [syn: {filamentous}, {filamentlike},
            {threadlike}, {thready}]