Source : Webster's Revised Unabridged Dictionary (1913)

Shellbark \Shell"bark`\, n. (Bot.)
   A species of hickory ({Carya alba}) whose outer bark is loose
   and peeling; a shagbark; also, its nut.

Source : WordNet®

shellbark
     n : North American hickory having loose gray shaggy bark and
         edible nuts [syn: {shagbark}, {shagbark hickory}, {shellbark
         hickory}, {Carya ovata}]