filiform

from WordNet (r) 3.0 (2006)

filiform
    adj 1: thin in diameter; resembling a thread [syn:
           {filamentous}, {filiform}, {filamentlike}, {threadlike},
           {thready}]

from The Collaborative International Dictionary of English v.0.48

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]}.
   [1913 Webster] Filigrain