What does the weather forecast mean by precipitation of 60mm?

The weather forecast precipitation of 60mm refers to the precipitation of 60mm within 24 hours.

Precipitation is a measure of precipitation in a region. The total amount of water vapor contained in the air column is also called precipitable water. Corresponding to all the moisture in the air condenses into precipitation that can be formed when rain and snow fall. Precipitation refers to the depth at which liquid and solid (after melting) precipitation falls from the sky to the ground and accumulates on the horizontal plane without evaporation, infiltration and loss. Its unit is millimeters.