What is typically sold as an "Ameraucana", "Araucana", "Americana", or "Americauna", is, 95% of the time, an Easter Egger. True Ameraucanas and Araucanas are not sold by hatcheries, Easter Eggers are. They were both created in their modern form from crossbreedings of South American Araucanas and various other production breeds in the 1970s, but the first two are true breeds and the third one is a specific type of mutt.
Ameraucanas will:
Always be a specific color; e.g. Blue, Black, Wheaten
Always lay a blue egg
Always have ear muffs and a beard
Usually come from a private breeder
Araucanas will:
Always be a specific color; e.g. Blue, Black, Wheaten
Always lay a blue egg
Always have ear tufts (NOT muffs) and a beard
Always be rumpless (this does not apply to birds in UK or Australia)
Usually come from a private breeder
Easter Eggers will:
Be any color or mixture of colors
Usually lay a blue OR green egg but sometimes brown, white, tinted, etc.
Usually have a muff/beard but not always
Usually come from a hatchery