A round of cell growth and proliferation in cell culture.

The ability of stem cells from one adult tissue to generate the differentiated cell types of another tissue.

Ability of a single stem cell to give rise to all of the various cell types that make up the body. Pluripotent cells cannot make so-called "extra-embryonic" tissues such as the amnion, chorion, and other components of the placenta.

With regard to an embryo, preimplantation means that the embryo has not yet implanted in the wall of the uterus. Human embryonic stem cells are derived from preimplantation stage embryos fertilized outside a woman's body (in vitro).

Expansion of cells by the continuous division of single cells into two identical daughter cells.