Definition
The application of oil or grease between moving parts of an engine or mechanical system to reduce friction, carry away heat, flush contaminants, and protect surfaces from wear and corrosion.
Plain English
Coating moving metal parts with oil or grease so they slide smoothly instead of grinding against each other, while also keeping them cool and clean.
Context Anchor
Encountered in aircraft systems, engine operation, preflight inspections, and maintenance discussions whenever oil level, grease points, or moving parts are mentioned.
Derivation
From the Latin lubricare, meaning 'to make slippery.' The aviation meaning keeps that core idea but adds the jobs of cooling, cleaning, and protecting metal surfaces inside an engine.
Why Pilots Care
An engine that loses lubrication can seize within minutes. Checking oil quantity and condition before every flight, and watching oil pressure and temperature in flight, are basic safety habits because lubrication failure is one of the fastest ways to lose an engine.
Intuition Check
Lubrication is not just “making something slick.” In an aircraft system, it also helps control heat, reduce wear, and protect parts from damage.
Example Sentence 1
During preflight, the pilot checked the dipstick to confirm the engine had enough oil for proper lubrication.
Example Sentence 2
Low lubrication in the propeller hub can cause vibration and premature wear.