a combining form meaning “seven,” used in the formation of compound words: heptahedron.
Also especially before a vowel, hept-.
Origin of hepta-
< Greek, combining form of heptá seven; cognate with Latin septem; akin to Old English seofon seven
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
before a vowel hept-
Word Origin for hepta-
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
before vowels hept-, word-forming element meaning "seven," from Greek hepta "seven" (see seven).
Online Etymology Dictionary, © 2010 Douglas Harper
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.