One of the mysteries of the English language finally explained.
Definition of olein in English:
olein
(also oleine)
noun
ChemistryA glyceryl ester of oleic acid; specifically glyceryl trioleate, C₃H₅(C₁₈H₃₃O₂)₃, a colourless oily liquid which is a very common natural fat (also called triolein). Also (more widely): any liquid fat (consisting chiefly of such esters) separated from a solid or semi-solid fat; (formerly, also) †a glyceride of a fatty acid other than oleic acid (obsolete).
Origin
Mid 19th century; earliest use found in Thomas Thomson. From French oléine from classical Latin oleum oil + French -ine; compare -in.