Lubricating oil; a lubricant used to reduce friction between machine parts (e.g., engine oil).
機械には定期的に潤滑油を差してください。
Please apply lubricating oil to the machine regularly.
車のエンジンオイルも潤滑油の一種だ。
Car engine oil is also a type of lubricating oil.
潤滑油が切れると金属部品がすぐに摩耗する。
If lubrication runs out, metal parts will wear down quickly.
Figuratively, a person or thing that helps make processes run smoothly; a facilitator or mediator.
彼はプロジェクトの潤滑油のように、意見の調整をしてくれた。
He acted like a lubricant for the project, smoothing out disagreements.
この合意が両社の交渉の潤滑油になった。
This agreement served as a lubricant for negotiations between the two companies.