Webster’s Revised Unabridged Dictionary · 1913
Lubricant
Lu′bri·cant, a. [L. lubricans, p. pr. of lubricare, See Lubricate.] Lubricating.
Lu′bri·cant, n. That which lubricates; specifically, a substance, as oil, grease, plumbago, etc., used for reducing the friction of the working parts of machinery.