Term: hydrogen (H)
Origin: Anc Greek ύδωρ/hydor (=water) + γένος/genos(=generation, produced by) because it forms water when exposed to oxygen.
Coined:
In 1778 by French chemist Antoine-Laurent Lavoisier (1743-1794).
Definition:
Hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass
