un·un·hex·i·um (?-n?n?h?k?s?-?m)n. See element 116.[Latin ?nus, one; see oi-no- in Indo-European roots + Latin ?nus + Greek hex-, hex- + -ium (in reference to its atomic number).]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.