A group or series of six.
[Late Latin hexas, hexad-, the number six, from Greek, from hex, six; see s(w)eks in the Appendix of Indo-European roots.]
hex·adic (hĕk-sădĭk) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.