Clairaut, Alexis Claude, a French mathematician and astronomer, born at Paris, of so precocious a genius, that he was admitted to the Academy of Sciences at the age of 18; published a theory of the figure of the earth, and computed the orbit of Halley's comet (1713‒1765).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Clair, St. * Clairvaux