common-law marriage: a marriage relationship created by agreement and cohabitation rather than by ceremony
marriage: the state of being a married couple voluntarily joined for life (or until divorce)
parity bit: (computer science) a bit that is used in an error detection procedure in which a 0 or 1 is added to each group of bits so that it will have either an odd number of 1's or an even number of 1's; e.g., if the parity is odd then any group of bits that arrives with an even number of 1's must contain an error