The definition of lye is an alkaline solution that is often a mix of potassium or hydroxide or sodium which is generally used for cleaning.(noun)
A strongly alkaline solution used to make soap is an example oflye.
See lye in Webster's New World College Dictionary
Origin: ME lie < OE leag, akin to Ger lauge < IE base *lou-, to lave
See lye in American Heritage Dictionary 4
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