legendrian

from The Century Dictionary.

• Pertaining to or invented by the eminent French mathematician Adrien Marie Legendre (1752–1833).
• a symbol, looking like a fraction in parenthesis, used in the theory of numbers. It is equal to plus or minus unity, according as the numerator is or is not a quadratic residue of the denominator. It vanishes if the numerator is divisible by the denominator.