lubricant
n.a substance like oil or grease that you put on surfaces to help them move smoothly against each other. It stops parts from rubbing together and getting too hot or damaged.
n.a substance, such as oil or grease, applied to surfaces to reduce friction and wear between moving parts. Often used metaphorically to describe something that eases social or political interactions.
“The mechanic applied a lubricant to the squeaky door hinge.”
“Industrial machines require a high-quality lubricant to prevent the metal components from overheating during continuous operation.”
“While the primary function of the fluid is to act as a lubricant, it also serves as a coolant by carrying heat away from the engine's internal combustion chamber.”
Countable when referring to specific types or brands of the substance; uncountable when referring to the substance in general.
“Where it stays liquid, it acts as a lubricant along the surfaces where rock and ice meet.”
“Clear Eyes Maximum Itchy Eye Relief is marketed on its packaging as an astringent/lubricant redness-reliever eye drop intended to provide relief from redness, itching, burning and watery eyes.”
From lubricate + -ant.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.