A
part (or
voice) is a strand or
melody of
music played by an individual
instrument or
voice (or group of identical instruments or voices) within a larger work. Parts may be referred to as an
outer part (the top and bottom parts) or an
inner part (those in between).
Part-writing (or
voice leading) is the composition of parts in consideration of
harmony and
counterpoint. In the context of
polyphonic composition the term
voice may be used instead of
part to denote a single
melodic line or
textural layer. The term is generic, and is not meant to imply that the line should necessarily be
vocal in character, instead referring to
instrumentation or simply to
register.