What does the word potency mean?

Usage examples for potency

  1. Moreover, so great was its potency, that two or three drops in a gallon of water formed a mixture of wonderful therapeutic value. – Primitive Psycho-Therapy and Quackery by Robert Means Lawrence
  2. Nor is this an empty form, for upon an occasion this person himself witnessed a very bitter contention between a keeper of the barrier and one whose token had through some cause lost its potency. – The Mirror of Kong Ho by Ernest Bramah