The SI definition of 1 meter is the distance travelled by light in a vacuum during a time interval of 1/299,792,458 of a second. In other words, the meter is defined as the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second. This definition was established in 1983 by the International Committee for Weights and Measures (CIPM) and is the current accepted definition of the meter. This definition is based on the fundamental physical constant of the speed of light, which has a constant value and can be reproduced in laboratories around the world with great accuracy. By defining the meter in this way, it provides a consistent and universally recognized standard for length measurement.