megakaryocyte /(mĕg`ȧ*kăr"ĭ*ō̇*sīt)/

meg·a·kar·y·o·cyte

megakaryocyte

n.
  1. 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 μm in diameter, with a polyploid nucleus. Also referred to as megacaryocyte, megalokaryocyte, and thromboblast. (Anat.)