Is it ensure, insure, or assure?
1650s, "any small particle," from Latin corpusculum "a puny body; an atom, particle," diminutive of corpus "body" (see corporeal). First applied to blood cells 1845. Related: Corpuscular.
corpuscle cor·pus·cle (kôr'pə-səl, -pŭs'əl)n.
An unattached body cell, such as a blood or lymph cell.
A rounded, globular mass of cells, such as the pressure receptor on certain nerve endings.
Any of various cellular or small multicellular structures in the body, especially a red or white blood cell.