Webster's Revised Unabridged Dictionary · 1913

Potency

Potency , noun

[Latin potentia, from potens, -entis, potent. See Potent, and compare Potance, Potence, Puissance.]

The quality or state of being potent; physical or moral power; inherent strength; energy; ability to effect a purpose; capability; efficacy; influence.
Drugs of potency. — Hawthorne
A place of potency and away o' the state. — Shakespeare