(chemistry) The divalent radical formed from two separate hydrogen atoms or ions / (chemistry, modifying a noun) Describing a dihydrogen bond / (inorganic chemistry) The hydrogen molecule H₂

(chemistry) hydrogenated with the addition of two atoms of hydrogen per molecule

Alternative spelling of dihydrogen monoxide

(inorganic chemistry, usually humorous) H₂O, water.

(inorganic chemistry, nonstandard) An alternative systematic name for water, H₂O.

Alternative spelling of dihydrogen monoxide