No, thats not a typo, there are all kinds of acrylics, even acrylic lacquers, but those are mainly found in automotive paints. I have never used an acrylic enamel before, I can't even say that I have seen them, but I am sure they are out there. They are probably geared more for artwork than model work, but who knows?
One more thing, check out the FAQ section, it will answer your question about how an enamel can be considered an acrylic.