heptad

[ hep-tad ]
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noun
  1. the number seven.

  2. a group of seven.

  1. Chemistry. an element, atom, or group having a valence of seven.

Origin of heptad

1
First recorded in 1650–60, heptad is from the Greek word heptad- (stem of heptás). See hepta-, -ad1

Words Nearby heptad

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use heptad in a sentence

  • But this oddness belongs to other numbers also (pentad, heptad, &c.).

    Aristotle | George Grote
  • heptad, a term in chemistry to denote an atom that is the equivalent of seven atoms of hydrogen, from hepta, seven.

    The Nuttall Encyclopaedia | Edited by Rev. James Wood

British Dictionary definitions for heptad

heptad

/ (ˈhɛptæd) /


noun
  1. a group or series of seven

  2. the number or sum of seven

  1. an atom or element with a valency of seven

Origin of heptad

1
C17: from Greek heptas seven

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012