What is "cloud base"

n. The altitude of the base of a mass of cloud; measured by a ceilometer.

This article refers to meteorology. For the airborne base of the TV series Captain Scarlet and the Mysterons, see Cloudbase.

The cloud base (or the base of the cloud) is the lowest altitude of the visible portion of the cloud. It is traditionally expressed either in m or feet above mean sea level (or planetary surface), or as the corresponding pressure level in hectopascal (hPa, equivalent to millibar).