It's from the Book of Kells. Where it is one of the four traditional winged figures representing the Evangelists. It is the symbol for Saint Mark; with the ox representing Saint Luke; the eagle, Saint John; and the man, Saint Matthew.
It's a gryphon.. a mythical creature.. originally I thought it was a sort of gothic angel, but its definitely a gryphon. I'm actually going to get this tattoo done on my ankle. I love the design and it will be my first tattoo in honor of my 50th birthday which is coming up.. As for the A, well my hubbies name starts with A so It can represent either Angel or my hubbie (both hotties)