Definition of the word level off

The phrase "level off" originated in the mid-1900s. The term comes from the context of aviation, specifically when a pilot is maneuvering a plane to maintain a constant altitude. In this context, "leveling off" refers to the action of stabilizing the aircraft after a climb, descent, or turn. The verb "level" itself comes from the Old English word "leofan," which means to make level or equal. The usage of "level off" in aviation terminology can be traced back to the 1930s, when the popularity of flying increased and communication between pilots and air traffic control became more necessary. The meaning of "level off" expanded beyond aviation in the mid-20th century. In its broader sense, it is used to describe a situation where a trend or rate of change has plateaued, whether it's in terms of speed, altitude, or a specific quantity. For example, sales may level off after a period of growth, or a market may stabilize after a period of volatility. The expression "level off" is now commonly used in everyday language to indicate a slowing down or flattening out of a process or trend.