Composer
Person who writes music 
Symphony 
A large piece for orchestra with four sections
Chord
Two or more pitches sounding at the same time
Dynamics
The louds and softs of music
Interval
The distance between two pitches
Pitch
the lowness and highness of   musical sounds
Score 
A book showing parts for instruments or voices for a piece of music
Double bar line 
Two vertical lines at the end of each piece