The way we perceive time passing (i.e. something boring seems to last twice as long)
Clock time
The way time actually passes.
Notes
Discrete events where loudness and pitch change
Beat
Regular division of time that is the grid that music fits within.
Nonpulsatile
Music that defies interpretation of a period pattern of notes.
Nonmetric
Music that defies interpretation of a period pattern of notes.
Quasi-pulsatile
Notes of more or less the same length follow each other, but the rhythm is hard to pin down to a constant pulse.
Tempo
The rate at which the beat passes by
Accelerando
Gradual speedup of temp
Ritardando
Gradual slowing down of tempo
Rallentando
Gradual slowing down of tempo
Meter
The way in which beats are organized in a piece of music. An organization of beats, divisions of beats, and groupings of beats into distinct levels of the passage of time.
Triple meter
Meter that groups beats into threes
Duple meter
Meter that groups beats into twos
Compound meter
Meter that divides beats in three
Simple meter
Meter that divides the beat in two
Syncopation
The metrical stress of a note is displaced in the meter so that the emphasis occurs on normally unstressed beats and carry through stressed beats
Accent
Shifted stress by playing them more loudly or giving them a harder attack
Loudness
Volume of the music. Artful contrasts in loudness often make effective musical expression.