SCORE (O.E. scor, from sceran, to cut, notch, cf. " shear ")  , properly a notch or groove cut in a piece of wood, called a " tally " (q.v.), as a method of counting ; hence an account or reckoning made in this way . Either from a custom of keeping each series of twenty numbers or notches on a separate tally, or of marking the twentieth number by a longer or deeper mark, the word was early used to denote the number twenty; it is still used as a measure of weight, equivalent to 20 Ib, computing the weight of animals sold for slaughtering for food . In music, a score is the written or printed copy of a composition on two or more staves, barred and braced together . For instrumental and vocal music a " full score " has the parts for each class of voice and instrument on a separate staff .