Osteoblast (from the Greek combining forms for "bone", ὀστέο-, osteo- and βλαστάνω, blastanō "germinate") are cells with single nuclei that synthesize bone. However, in the process of bone formation, osteoblasts function in groups of connected cells. Individual cells cannot make bone, and the group of organized osteoblasts together with the bone made by a unit of cells is usually called the osteon; the basis of this is discussed in "Organization and ultrastructure of osteoblasts" below.