tie
combines the value of two notes of the same pitch together into one longer sound
triplet
a group of three notes played in the time of two notes of the same value
time signature
groups beats into measures; used to show the meter, or recurring pattern of strong and weak beats, in a piece of music
anacrusis
note or series of notes written before the downbeat
simple time signatures
basic beat typically subdivided into two
compound time signatures
basic beat is subdivided into groups of three