Noun
quadratic residue (plural quadratic residues)
(number theory, modular arithmetic) For given positive integer n, any integer that is congruent to some square m modulo n.
An integer a is a quadratic residue modulo p if it is congruent to a perfect square modulo p and is a quadratic nonresidue modulo p otherwise. Source: Internet
These are the nonzero codewords of the quadratic residue code of length 7 over the field of 2 elements. Source: Internet
See also the article quadratic residue for details. Source: Internet