Main Entry: lye

Pronunciation: \ˈlī\

Function: noun

Etymology: Middle English, from Old English lēag; akin to Old High German louga lye, Latin lavare, lavere to wash, Greek louein

Date: before 12th century

1 : a strong alkaline liquor rich in potassium carbonate leached from wood ashes and used especially in making soap and for washing; broadly : a strong alkaline solution (as of sodium hydroxide or potassium hydroxide)
2 : a solid caustic (as sodium hydroxide)