IPA: /ˌhɛməˈpɔɪəsɪs/
KK: /hɛməˈpɔɪəsɪs/
The process by which blood cells are produced in the body.
Hemopoiesis occurs primarily in the bone marrow, where new blood cells are formed.
Hemopoiesis is formed from "hemato-" (from Greek "haima", meaning blood) and "poiesis" (from Greek "poiein", meaning to make or produce). The term refers to the process of making or producing blood.
Think of 'blood' ('hemato-') being 'made' ('poiesis') in the body — that's what hemopoiesis means.