Grease/ɡriːs/ Definition 1 of 5Pro Tip 1/3Machinery Maintenance Grease is essential for reducing friction in machines. Regularly grease the bearings to enhance their lifespan. Pro Tip 2/3Not Always Visible Grease in machines might not be obvious but is always crucial. Even if you don't see it, there's grease inside the motor. Pro Tip 3/3Prevention of Damage Using grease protects parts from wear and tear. To avoid breakdowns, don't forget to grease moving components.