Past tense of 'card,' meaning either to comb or straighten fibers like wool or cotton, or to ask someone to show identification to verify age.
From 'card' (a tool with wire teeth), from Middle Dutch 'kaarden,' ultimately from Latin 'carere' (to card wool). The 'check ID' meaning is recent American slang.
Before machines, people spent hours 'carding' wool by hand—today it takes seconds—so 'carding' is one of those manual skills that factories completely automated away, though the word stuck around.
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