(cosmology) the ratio of the speed of recession of a galaxy (due to the expansion of the universe) to its distance from the observer; the Hubble constant is not actually a constant, but is regarded as measuring the expansion rate today

an oriental tobacco pipe with a long flexible tube connected to a container where the smoke is cooled by passing through water

a constant in the equation of a curve that can be varied to yield a family of similar curves

any factor that defines a system and determines (or limits) its performance

a quantity (such as the mean or variance) that characterizes a statistical population and that can be estimated by calculations from sample data

(computer science) a reference or value that is passed to a function, procedure, subroutine, command, or program

United States astronomer who discovered that (as the universe expands) the speed with which nebulae recede increases with their distance from the observer (1889-1953)