A Dictionary of Music and Musicians/Prick Song
PRICK SONG. The name given by old writers upon music to divisions or descant upon a Plain-song or Ground, which were written, or pricked, down, in contradistinction to those which were performed extemporaneously. (See Morley's Introduction, Second Part.) The term is derived from the word 'prick,' as used to express the point or dot forming the head of the note. Shakspere (Romeo and Juliet, Act ii. Sc. 4) makes Mercutio describe Tybalt as one who 'fights as you sing prick song, keeps time, distance, and proportion; rests me his minim rest one, two, and the third in your bosom.' The term 'pricking of musick bookes' was formerly employed to express the writing of them. Payments for so doing are frequently found in the accounts of cathedral and college choirs.
[ W. H. H.