Or simple use it as it stands for women of courage in all fields :?
# A woman noted for courage and daring action.
# A woman noted for special achievement in a particular field.
# The principal female character in a novel, poem, or dramatic presentation
Yeah, even though they sound the same heroin and heroine are completly different words, with total different meanings. lol. The definition of heroine is what wot says above. It's basically just the female variant of a hero.