A cadence in tonal music is a progression of chords that marks the end of a phrase or section. Different cadences create varying degrees of closure according to convention. Broadly speaking, a cadence creates a greater degree of closure if it ends on the tonic (chord I) than if it ends on another chord. Descriptions of the various different cadences can be found by following the links below.
Cadences that end on the tonic
Cadences that end on the dominant