From Conservapediachord, with notes being played in sequence rather than together. The word arpeggio means "In the manner of the harp". For example, a tonic C arpeggio could be played with the first, third and fifth notes of a chord. In this example, the arpeggio could be played C, E, G, C.
You can also play a chord as "rolled chord", and technically it would also be called an "arpeggio". The sign for this in music notation is a wavy line to the left of the chord. Usually, all but the highest note of the chord is played as grace notes preceding the beat of the top note. However, in some situations, the chord should be rolled after the beat. This is necessary, for example, when a large rolled chord in the left hand accompanies a melody in the right hand, or when the bass line needs to be played on the beat. Another type of rolled chord is written as a wavy line with an arrow pointing downwards; this notation indicates that the chord should be played from the top down.