Monophony means music with a single "part" and a "part" typically means a single vocal melody, but it could mean a single melody on an instrument of one kind or another. Polyphony means music with more than one part, and so this indicates simultaneous notes.
monophony is the simplest of musical textures, consisting of a melody. or a tune, basically sung by a one person or played by a an instrument player.
polyphony - the style of simultaneously combining a number of parts - a musical texture - generally speaking, the way that melodic, rhythmic
homophony - is a texture in which a primary part is supported by one or more additional strands that flesh out the harmony and often provide rhythmic contrast.
