Arpeggio

An arpeggio is the notes of a chord played one after another instead of all at once — also called a "broken chord". The word comes from the Italian arpeggiare, "to play the harp": an instrument where plucking notes one by one, rather than all together, is the natural way to play.

Between a strummed chord and a scale

An arpeggio sits between strumming a chord (every note at once) and playing a scale (notes that don't necessarily form a chord): it's the exact same notes as a strummed chord, just spread out over time instead of heard as a single block.

On Guitarshelf

The "Arpeggios" sheet type applies this technique to chord progressions already in the catalog: every chord in the grid is picked note by note instead of strummed.