Following this, the range (or compass) of used notes was extended to three octaves, and the system of repeating letters A–G in each octave was introduced, these being written as lower-case for the second octave (a–g) and double lower-case letters for the third (aa–gg). When the range was extended down by one note, to a G, that note was denoted using the Greek letter gamma (Γ). (It is from this that the French word for scale, "gamme" derives, and the English word gamut, from "Gamma-Ut", the lowest note in Medieval music notation.)