Definitions

1. noun

a chemical element that is the lightest and most abundant chemical element in the universe and is the basis of water (H2O) and is the fuel for the sun.

“The discovery of dihydrogen led to major breakthroughs in our understanding of the universe and its composition.”

2. noun

a gas used as a fuel in spacecraft and as a propellant in some rockets.

“The spacecraft’s fuel system relied on dihydrogen to power its propulsion system.”