a small planet and the farthest known planet from the sun; has the most elliptical orbit of all the planets; "Pluto was discovered by Clyde Tombaugh in 1930"
(Greek mythology) the god of the underworld in ancient mythology; brother of Zeus and husband of Persephone
the act or process of assigning numbers to phenomena according to a rule; "the measurements were carefully done"; "his mental measurings proved remarkably accurate"