The Answer is Gazelle.
Its gazelle
A three letter African antelope is the "gnu", which ends in a "u" not a "you". The more common name for the gnu is the wildebeeste, but that won't fit into your crossword puzzle.
I don't think there is one. There is a type of Waterbuck (a type of Antelope) that is called the Lechwe, maybe that is what you are thinking of?
Eland is a type of Asian Antelope
on the range, where the deer and the antelope play
what landform is antelope canyon
The Bongo is a type of antelope that has a brown coat with then white stripes. This is the largest of the African antelope species.
A gnu is a wildebeest, which is a type of antelope.
A Gazelle
No, it is not.
Buffalo is not really an antelope, but it is the closest relative to the antelope where the name ends with an o.
A Nilgai is a type of antelope.