|Definition - The German dialect that currently prevails in media, literature, religion, education, and commerce.|
Etymology - It was so called because it was the version of German spoken in High (i.e. southern) Germany. As opposed to Low German (aka Plattdeutsch), the general name for all non-High-Germanic dialects of German — including English, Dutch, and Frisian.
Oxford English Dictionary - The term's first citation — one which clearly demonstrates the vibrant and enduring tradition of Anglo-Germanic hostility — is from 1611:
"A name which Ide teare out From the hye Germaines throat."
(Middleton & Dekker Roaring Girl Eivb)