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Meaning of dertrum

der•trum

Pronunciation: (dûr'trum), [key]
— pl. -tra
  1. the extremity of the maxilla of a bird's bill, esp. when hooked or differentiated from the rest of the bill, as in pigeons and plovers.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.