What's the difference between i.e. and e.g.?
in music, a short, recurring melodic pattern in the bass part of a composition that serves as the principal structural element. Prototypical instances are found in 13th-century French vocal motets as well as in 15th-century European dances, where a recurrent melody served as a cantus firmus, or fixed theme. With the rise of idiomatic instrumental music in the 16th century, the practice of improvising or composing new melodies above a repeated bass pattern became widely popular, especially in music for the lute and guitar (especially in Italy, England, and Spain) and harpsichord (especially in England); this practice, known in Spanish music as diferencias and elsewhere in Europe as divisions, is an early manifestation of the technique of theme and variations.