A collection of two or more notes played simultaneously. Root position refers to the standard organisation of the tonic note with two notes stacked above (usually a third and fifth above the tonic). A first inversion chord contains the same notes but starts on the third and a second inversion chord starts on the fifth. Chords can have added notes, such as a seventh, and can be identified and described using Roman numerals (e.g. V, I) or chord names (e.g. C Major).