Origin of Castile soapMiddle English Castell sope, after Castile, where first made
Castile soapCastile soap
also cas·tile soap
Origin of Castile soapAfter Castile
(countable and uncountable, plural Castile soaps)
- A kind of fine, hard, white or mottled soap, originally made with olive oil.
From Castile in Spain, from which it originally came.