There's a continuum of development in stemcells, and various terms have been invented to more or less indicate the level of development.
Might be better to use those terms than to mess around with "differentiate" ~ particularly since that term has a quite ordinary meaning related to how I or you might see different things.
I am using NIH definitions.
--Just being consistent with the definitions posted at Wikipedia, I think you are trying to use "differentiate" in place of several other terms.--
Stem cells are primal cells that retain the ability to renew themselves through cell division and can differentiate into a wide range of specialized cell types.
Adult stem cells are undifferentiated cells found throughout the body that divide to replenish dying cells and regenerate damaged tissues.