Heptad

Heptad, a term in chemistry to denote an atom that is the equivalent of seven atoms of hydrogen, from hepta, seven.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)

Hephæstos * Heptarchy, Anglo-Saxon
[wait for the fun]
Henry VIII.
Henry III.
Henry IV.
Henry IV.
Henry of Huntingdon
Henry the Navigator
Henry, Matthew
Henry, Patrick
Henryson, Robert
Hephæstos
Heptad
Heptarchy, Anglo-Saxon
Heptateuch
Hera
Heracles
Heracli`dæ
Heraclitus
Heraclius
Herat
Hérault
Herbart