early 15c., "endurance, fortitude" (in the face of pain, hardship, etc.), from Old French tolerance (14c.), from Latin tolerantia "a bearing, supporting, endurance," from tolerans, present participle of tolerare "to bear, endure, tolerate" (see toleration). Of individuals, with the sense "tendency to be free from bigotry or severity in judging other," from 1765. Meaning "allowable amount of variation" dates from 1868; and physiological sense of "ability to take large doses" first recorded 1875.