septilateral

sep·ti·lat·er·al

 (sĕp′tə-lăt′ər-əl)
adj.
Seven-sided.

[Latin septem, seven; see septet + lateral.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

septilateral

(ˌsɛptɪˈlætərəl)
adj
(Mathematics) having seven sides
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
In Peter Ackroyd's Hawksmoor (1985) it takes the (aberrant) form of a gnostic septilateral figure.