[ dur-truh m ]
/ ˈdɜr trəm /

noun, plural der·tra [dur-truh] /ˈdɜr trə/. Ornithology.

the extremity of the maxilla of a bird's bill, especially when hooked or differentiated from the rest of the bill, as in pigeons and plovers.

Origin of dertrum

1885–90; < New Latin < Greek dértron membrane, derivative of dérein to skin; compare dérma derma1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019