lye /laɪ/noun 3verb 1forms 5 noun3 •An alkaline liquid made by leaching ashes (usually wood ashes). •Potassium or sodium hydroxide (caustic soda).She had not left the lye in too long so that the hair would fall out in clumps later. — 2019 •(UK) A short side line, connected with the main line; a turn-out; a siding.Brakevan lye. [same page in the main text] There is also an inclined lye for brakevans at each end of the yard. — 1962 verb1 •To treat with lye. formslyed · lyeing · lyes · lyeth · lyest
