# Path length

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*in Wiktionary, the free dictionary.***path length****Path length** can refer to:

## Physics[edit]

- 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[edit]

- 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