D defs.my
Entry 1 sense Webster, 1913

Heptavalent

· Hep·tav·a·lent · IPA
01 a. Having seven units of attractive force or affinity; -- said of heptad elements or radicals.
  1. 1.
    Having seven units of attractive force or affinity; -- said of heptad elements or radicals.(Chem.)