myeloplax

from The Century Dictionary.

• noun A large multinucleated protoplasmic mass, occurring in the marrow, especially in the neighborhood of the osseous substance.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Anat.) One of the huge multinucleated cells found in the marrow of bone and occasionally in other parts; a giant cell. See osteoclast.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun anatomy One of the huge multinucleated cells found in bone marrow and occasionally in other parts; a giant cell.