What is the Eastern Hemisphere?
The opposite half of the earth you’re not standing on depending on which direction you face.
So if you’re facing westward the other half is eastern and vice versa.
From Wikipedia:
The Eastern Hemisphere is a geographical term for the half of Earth which is east of the prime meridian (which crosses Greenwich, London, United Kingdom) and west of the antimeridian (which crosses the Pacific Ocean and relatively little land from pole to pole).