"Loss by Friction" is a term that refers to the loss of energy or power when two surfaces are rubbed against each other. It is often used in the context of engineering where it is an important consideration in the design of machines and mechanical systems. There are several synonyms for "loss by friction" which can be used interchangeably. Some of these include "frictional loss," "drag," "resistance," "frictional force," "wear and tear," and "mechanical inefficiency." All these terms highlight the negative impact of friction on the efficiency of machines and systems, and emphasize the need for addressing it through adequate lubrication and design optimization.