In music, events are discrete actions that result in the production of sound.
David Cope defines an event as an ordered collection of five essential attributes, where one note corresponds to one list of five parameters:

(0 60 500 1 127)

The positioning of parameters inside a list indicates their attributes. From left to right, the parameters in a list represent the attack time (on-time) in milliseconds, the MIDI key number (60 equals to middle C, 61 to C sharp, 59 to B, and so forth), the duration (where 1000 usually represents a quarter-note, 500 an eighth note, 2000 an half-note, etc.), the MIDI channel number (which allows for instrumental or voice differentiation), and the note velocity (where 0 is the softest, and 127 the loudest possible). On-times are relative to the metronomic indication in use. With the metronome set to quarter-note = 120, for example, an on-time of 1000 would actually be played 500 milliseconds after zero.
Typically events in a list appear sorted by their on-times.