Emily Dickinson Lexicon

HEP'TA-CHORD, n. [Gr. επτα, seven, and χορδη, chord.]

A system of seven sounds. In ancient poetry, verses sung or played on seven chords or different notes. In this sense the word was applied to the lyre, when it had but seven strings. One of the intervals is also called a heptachord, as containing the same number of degrees between the extremes. Encyc.