The Etymology of Bleach
Bleach is one of the great paradoxes of English etymology. The Old English verb blǣcan meant to whiten, and the related adjective blǣc meant pale — but blæc (with a slightly different vowel) meant black. Both come from the same Proto-Indo-European root *bʰleyǵ-, meaning to shine or gleam, which in Germanic split along the two outcomes of fire: the pale ash that remains and the charred wood that burns. Different daughter languages picked up different ends of the spectrum, leaving English with two paradoxical descendants. The verb sense — to deliberately remove colour — is medieval; commercial bleaching of linen and cotton was a major industry from the 17th century onward, originally using sour milk and sunshine before chlorine was introduced in 1785. Modern bleach as a noun for a sodium hypochlorite or peroxide solution dates from the late 19th century. The word still carries its original glow: when something is bleached, it shines.