Texture
Different layers and parts of a musical piece and how they fit together
Monophonic
A single melodic voice or instrument
Polyphonic
Different musical lines that interweave with each other
Homophonic
A texture based on chords
Counterpoint
Two or more different melodies playing together
Unison
When two or more voices or instruments sing/play exactly the same thing at the same time
Parallel Motion
Notes moving in the same direction keeping the same interval
Contrary Motion
Notes moving in opposite directions; one up, the other down