the rate at which the expansion velocity of the universe depends on distance away. It is currently estimated to lie in the range 60–80 km s–1 megaparsec–1
Also called: Hubble parameter
Hubble constant in American English
US
a ratio expressing the rate at which the universe is expanding, the so-called constant in Hubble's law, equal to the velocity of a receding galaxy divided by its distance from the earth: symbol, H0