The Collaborative International Dictionary
megacaryocyte
megakaryocyte \meg`a*kar"y*o*cyte\ (m[e^]g`[.a]*k[a^]r"[i^]*[-o]*s[imac]t) n. (Anat.) A large bone marrow cell not usually found in the circulating blood; it is regarded as the precursors of blood platelets; it is up to 100 [mu]m in diameter, with a polyploid nucleus. Also referred to as megacaryocyte, megalokaryocyte, and thromboblast.
Wiktionary
megacaryocyte
n. (alternative form of megakaryocyte English)