turned black, or lost consciousness; also used in 'blacked out' meaning to lose memory or awareness.
From Old English 'blæc' meaning 'black, dark, or stained'. The past tense 'blacked' can mean literally coloring something black or the slang term for losing consciousness.
When people 'black out' from drinking or emotion, they're not actually turning black—but ancient people called the color black 'blæc' (stained), so 'blacked out' originally meant your mind became stained or obscured.
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