Roman numerals: Roman numerals are another system of numerical notation that uses letters from the Latin alphabet. In music theory, Roman numerals are used to represent chords and analyze harmonic relationships within a key.
Figured bass: Figured bass is a shorthand notation system used in Western classical music during the Baroque era. It uses numbers below or above the bass note to indicate which intervals should be played above it.
Chord symbols: Chord symbols are abbreviated notations used in popular music and jazz to represent chords. They often consist of letter names combined with additional symbols or numbers indicating chord quality and extensions.