Late Middle English: from medieval Latin gamma ut, originally the name of the lowest note in the medieval scale (bass G an octave and a half below middle C), then applied to the whole range of notes used in medieval music. The Greek letter Γ (gamma) was used for bass G, with ut indicating that it was the first note in the lowest of the hexachords or six-note scales (see solmization).

• To run the gamut is to experience or display the complete range of something. In medieval music gamut was originally the name of the lowest note in the scale, but the term also came to be applied to the full range of notes which a voice or instrument can produce. In time it started to be used outside musical contexts. According to the acerbic American critic and humorist Dorothy Parker, the film actress Katharine Hepburn ‘ran the whole gamut of emotions from A to B’. This word is from medieval Latin gamma ut, and applied to bass G an octave and a half below middle C. The Greek letter Γ (gamma) was used for bass G, with ut indicating that it was the first note in the lowest of the hexachords or six-note scales. Notes in each hexachord were named using syllables of a Latin hymn for St John the Baptist's Day in which each line began on the next note of the scale: Ut queant laxis resonare fibris Mira gestorum famuli tuorum, Solve polluti labii reatum, Sancte Iohannes. A seventh note, si, was added later, from the initial letters of Sancte Iohannes ‘St John’. The scheme was adapted in the 19th century for the Tonic Sol-fa.