Source : Webster's Revised Unabridged Dictionary (1913)

Conchylaceous \Con`chy*la"ceous\, Conchyliaceous
\Con*chyl`i*a"ceous\, a. [L. conchylium shell, Gr. ?, dim. of ?,
   equiv. to ?. See {Conch}.]
   Of or pertaining to shells; resembling a shell; as,
   conchyliaceous impressions. --Kirwan.