What is defanishon of hemosper?

It seems there might be a typo in your question, as "hemosper" does not appear to be a recognized term in English. If you meant "hemisphere," it refers to half of a spherical object, commonly used in geography to describe the Earth's division into the Northern and Southern Hemispheres or the Eastern and Western Hemispheres. If you meant something else, please clarify, and I'll be happy to help!