At the beginning, let's look it up in a dictionary.
amazon BrE/ˈæməzən/ NAmE /ˈæməzɑːn/
noun countable
1 Amazon: a member of a group of female warriors in stories told by the ancient Greeks
We all know Wonder Woman is a true Amazon.
2 : a tall and strong woman
Brienne of Tarth is a brave blond amazon.
Now let's take a close look at it etymology.
from Greek Amazon (mostly in plural Amazones) "one of a race of female warriors in Scythia," possibly from an Iranian compound *ha-maz-an- "(one) fighting together" [Watkins], but in folk etymology long derived from a- "without" + mazos, variant of mastos "breast;" hence the story that the Amazons cut or burned off one breast so they could draw bowstrings more efficiently.
A bit scary, isn't it? And My trick to memerize this word: Am + a + zone.