That's a great question.
Genocide is an international crime. It's an atrocity crime that's defined very clearly in the genocide convention and in the Rome Statute of the International Criminal Court. I've already gone through that definition in my opening remarks, so I won't repeat it.
Ethnic cleansing, on the other hand, is not an atrocity crime that's under the jurisdiction of the Rome Statue of the ICC. Its definition can, though, be gleaned from a UN commission of experts that was tasked with looking into crimes committed in the former Yugoslavia. That commission defined ethnic cleansing as “rendering an area ethnically homogeneous by using force or intimidation to remove persons of given groups from the area.” That same commission, in its final report, defined ethnic cleansing as “a purposeful policy designed by one ethnic or religious group to remove by violent and terror-inspiring means the civilian population of another ethnic or religious group from certain geographic areas.” I know these two sentences are a bit of a mouthful, but essentially, that's ethnic cleansing.
Ethnic cleansing, in the context of Tigray, has been alleged and already supported with evidence by the likes of Human Rights Watch. It was also the subject of an internal U.S. government report, which found that Ethiopian officials were “deliberately and efficiently rendering Western Tigray ethnically homogeneous through the organized use of force and intimidation.” There was forced displacement and then repopulation of the regions.