Pressure-feed lubricating system is widely used in machines to lubricate the moving parts and reduce friction. However, there are few other synonyms that are used interchangeably with it. Some common alternatives include forced-feed lubricating system, oiling system under pressure, centralized lubricating system, and circulating lubrication system. These synonyms highlight the same concept of a lubrication system that supplies oil or grease under pressure to the moving parts of machinery. The basic principle behind all of these systems is to provide continuous lubrication to the machine parts to ensure smooth operation and prevent wear and tear. So, whether you call it a pressure-feed lubricating system or any other synonym, it all serves the same purpose in maintaining machine efficiency.