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Question #75204 posted on 11/15/2013 6:08 p.m.
Q:

Dear 100 Hour Board,

What is the scientific difference between a beak and a bill? Is there an official difference? If not, what is the unofficial difference? My preliminary google searches didn't give me anything definitive.

-The Platypus

A:

Dear Platypus,

If by scientific you mean ornithological, the OED has your back. Here's what it says about the usage of beak vs. bill:

In Ornithology, beak is the general term applicable to all birds; in ordinary language beak is always used of birds of prey, and generally when striking or pecking is in question; beak and bill are both used of crows, finches, sparrows, perching birds and songsters generally, bill being however more frequent; bill is almost exclusively used of humming-birds, pigeons, waders, and web-footed birds.

There appears to be only an unofficial difference. It's easier to think of as a visual:

BeakvsBill.png
In case you weren't talking about birds, here is the definition of beak and five definitions of bill, which have clear differences.

-Owlet