Merriam-Webster Collegiate Dictionary - potent

 I. adjective  Etymology: Middle English, from Latin ~-, potens (present participle of posse to be able), from Latin potis, pote able; akin to Gothic bruthfaths bridegroom, Greek posis husband, Sanskrit pati master  Date: 15th century  1. having or wielding force, authority, or influence ; powerful  2. achieving or bringing about a particular result ; effective  3.  a. chemically or medicinally effective a ~ vaccine  b. rich in a characteristic constituent a ~ drink  4. able to copulate — usually used of the male  • ~ly adverb  II. adjective  Etymology: obsolete English ~ crutch  Date: 1610 of a heraldic cross having flat bars across the ends of the arms — see cross illustration