Gräpʹto-līte or Grap-tōl'i thēs, n.

n. [Gr. γραπτός, engraved, written, from γράφειν, to write, and λίθος, stone.] (Geol.) A plume-shaped or penniform fossil of extreme delicacy, probably related to the modern sertularian zoöphytes, found in Silurian slates.