early 15c., "a vote to choose someone to decide a question," from Late Latin scrutinium "a search, inquiry" (in Medieval Latin, "a mode of election by ballot"), from Latin scrutari "to examine, investigate, search," from PIE root *skreu- "to cut; cutting tool" (see shred (n.)). Meaning "close examination" first recorded c. 1600. Perhaps the original notion of the Latin word is "to search through trash," via scruta (plural) "trash, rags" ("shreds"); or the original sense might be "to cut into, scratch."