from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The horny covering of the upper part of a bird's beak
from the GNU version of the Collaborative International Dictionary of English
- n. The sheath of the upper mandible of a bird.
from The Century Dictionary and Cyclopedia
- n. In ornithology, the integument of the upper mandible of a bird, exclusive of the dertrotheca.
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