What's the difference between ethnic cleansing and genocide?
Genocide is the systematic destruction of part or all of a specific group of people. Ethnic cleansing involves the removal of a specific group of people from one's midst, whether through genocide or mass expulsions. Both are recent terms for practices dating back to antiquity; "genocide" was coined in 1943, while the more euphemistic "ethnic cleansing" caught on as an English phrase in the 1990s.
For more on the legal definition of genocide and recent applicable cases, see Defining Genocide.