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a combining form meaning “seven,” used in the formation of compound words: heptahedron.
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Also especially before a vowel, hept-.

Origin of hepta-

<Greek, combining form of heptá seven; cognate with Latin septem; akin to Old English seofonseven
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021


What does hepta- mean?

Hepta- is a combining form used like a prefix meaning “seven.” It is used in a number of scientific and other technical terms.

In chemistry, hepta- is specifically used to indicate seven atoms or seven groups of atoms in compounds, e.g., heptachlor.

Hepta- comes from the Greek heptá, meaning “seven.” The English word seven, as different as it may look, is actually related to the Greek heptá.

What are variants of hepta-?

When combined with words or word elements that begin with a vowel, hepta- becomes hept-, as in heptane.

Examples of hepta-

One example of a word you may have encountered that features hepta- is heptagon, “a polygon having seven angles and seven sides.”

The first part of the word, hepta, means “seven,” as we know. The -gon portion of the word may also look familiar: it is a combining form meaning “angled” or “angular,” from the Greek gōnía. Heptagon literally translates to “seven-angled.”

Heptagon comes from the Greek heptágōnos, which features the equivalent form of hepta- in the language.

What are some words that use the combining form hepta- or hept-?

What are some other forms that hepta- may be commonly confused with?

Break it down!

The combining form -archy means “rule” or “government.” A government described as a heptarchy would be run by how many people?

How to use hepta- in a sentence

  • The Ptolemies united it to the mainland by means of a pier, named Hepta-stadium, in allusion to its length.

  • 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
  • Hepta- (in words of Greek origin), seven; as Heptagynous, with seven pistils or styles.

British Dictionary definitions for hepta-


before a vowel hept-

combining form

Word Origin for hepta-

from Greek
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

Medical definitions for hepta-


Containing seven atoms, molecules, or groups:heptane.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.