the.com/stem cell

means A cell that hasn't yet decided what kind of cell to become, able both to copy itself and to turn into specialized cell types the body needs.

from From 'stem' in its old botanical sense — the stalk or trunk from which branches grow — extended by 19th-century biologists to describe cells seen as the common origin-point of other cell lines. German scientists used 'Stammzelle' in this sense in the late 1800s, theorizing a single ancestral cell behind blood and tissue development; the English term followed the same branching logic, with one unspecialized cell as the 'trunk' from which specialized descendants sprout.