From the
Online Etymology:
score
Late O.E. scoru "twenty," from O.N. skor "mark, tally," also, in Icelandic, "twenty," from P.Gmc. *skura-, from PIE base *(s)ker- "to cut" (cf. O.E. sceran; see
shear). The connecting notion is perhaps counting large numbers (of sheep, etc.) with a notch in a stick for each 20. This counting notion is the origin of the modern sense in sports (1742, originally in whist). In O.Fr., "twenty" (vint) or a multiple of it could be used as a base, e.g. vint et doze ("32"), dous vinz et diz ("50"). Meaning "printed piece of music" first recorded 1701, from the practice of connecting related staves by scores of lines. The verb meaning "to cut with incisions or notches" is attested from c.1400; the slang sense "achieve intercourse" first recorded 1960. -Bill
