Lye

Part of speech: noun

Pronunciation: /laɪ/

Definitions

1. A highly alkaline compound used for making soap and cleaning products
2. A solution with a high pH used chiefly for cleaning and in soap production
3. An alkaline substance typically employed in industrial and household cleansing tasks

Etymology: Lye is one of the oldest cleaning agents in English, and its name goes back to the Old English "lēah" and "lēag," which described water that had been filtered through wood ash. Its ancestry runs back to a Proto-Germanic root meaning "to wash," so the word is essentially a name for the act of washing, applied to the substance that made washing possible. The word also has a surprising near-twin in English. "Lye" is a variant of "lie," the verb meaning to rest horizontally, and it survives in a specialised sense in building and paving, where a "lie" or bed of material is laid down. The two words look and sound identical today, yet they come from unrelated roots. Lye's cognates are spread across the Germanic languages, including Dutch "loog" and German "Lauge," both still meaning the same caustic solution. Because the word is so old and so widely shared, it preserves a very ancient household practice of making alkali from ashes and water.

Synonyms: sodium hydroxide, caustic soda, alkali, lye water, potash