Path length

Path length can refer to:

Physics

 * Distance, the total distance an object travels dependent on its path through space
 * Optical path length, the product of the distance light travels and the refractive index of the medium it travels through
 * Mean free path, the average distance that a particle travels before scattering
 * Radiation length, a characteristic length for the decay of radiation in a medium

Networks and computing

 * Average path length, the average number of steps along the shortest paths for all possible pairs of network nodes
 * Hop count, the number of intermediate network devices through which data must pass between source and destination in a computer network
 * Instruction path length, the number of machine code instructions required to execute a section of a computer program