Meaning

noun a member of a group of English Protestants who in the 16th and 17th centuries thought that the Protestant Reformation under Elizabeth was incomplete and advocated the simplification and regulation of

noun someone who adheres to strict religious principles; someone opposed to sensual pleasures

noun a person excessively concerned about propriety and decorum

originProbably from purity + -an, because they sought to purify Church of England worship of what they perceived as Roman Catholic aspects. The capitalised form preceded the lowercase form puritan.

Etymology from Wiktionary, CC BY-SA 3.0