Grease lubrication is a method of lubricating machinery using a semi-solid lubricant called grease. Grease is composed of base oil, thickener, and additives. It works by forming a protective film between moving surfaces, reducing friction and wear. The thickener acts as a sponge, holding the oil and releasing it gradually. Grease lubrication offers advantages such as improved sealing, water resistance, and extended lubrication intervals, making it suitable for various applications.