heptad

Definitions

  • WordNet 3.6
    • n heptad the cardinal number that is the sum of six and one
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Webster's Revised Unabridged Dictionary
    • n Heptad (Chem) An atom which has a valence of seven, and which can be theoretically combined with, substituted for, or replaced by, seven monad atoms or radicals; as, iodine is a heptad in iodic acid. Also used as an adjective.
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Century Dictionary and Cyclopedia
    • n heptad The sum of seven units; the number seven.
    • n heptad In chem., an atom whose equivalence is seven atoms of hydrogen, or which can be combined with, substituted for, or replaced by seven atoms of hydrogen.
    • n heptad In music, in the duodenal system of analysis, a scheme of seven tones, formed by uniting two duodenal cells of four tones. A heptad based on C would be Eb G—Ab C E—F A, and would contain all the tones that can enter into consonant triads with the tonic of the heptad, C. See duodene.
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Etymology

Webster's Revised Unabridged Dictionary
L. heptas, the number seven. Gr. , , fr. "epta` seven