這兩個術語適用於鳥類時，幾乎沒有差別，都可以用。
它們的區別是，
“beak”可以適用於很多動物，包括海龜，某些昆蟲，壹些魚，壹些哺乳動物，以及頭足類動物，而不只僅僅是鳥類。它還可以被用到許多恐龍身上。
而“bill”通常只適用於鳥喙或鴨嘴獸。尤其是當喙細長，扁平或弱，或屬於蹼足類或者鴿子屬的鳥類。
There is little difference between the two terms when applied to birds.
The term "beak" can refer to a wide range of other animals, not just
birds, including turtles, some insects, some fish, a few mammals, as
well as cephalopods. It can also be applied to many dinosaurs too.
However the term "bill" is normally only applied to the beak of a bird
or platypus. This is especially used when the beak is slender, flattened
or weak, or belongs to a web-footed bird or a bird of the pigeon
family.
希望對妳有所幫助，請采納。