(1629–95; b. The Hague, Netherlands; d. The Hague, Netherlands) Dutch mathematician, astronomer, and horologist. The son of a diplomat, Huygens studied law and mathematics, first at U Leiden and then at the College of Orange at Breda. His principal interest was astronomy, but this required precision instrumentation and led to his devising new methods for polishing lenses and keeping accurate time — in 1656 he patented the first pendulum clock. The previous year he had discovered the first of Saturn's moons. In 1657 he wrote the first printed work on probability, De Ratiociniis in Ludo Aleae (Calculation in Games of Chance).

A Dictionary of Statistics. Second edition revised. Copyright © Oxford University Press, 2008. All rights reserved.