hydrogen
1. [ noun ] (chemistry) a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe
Synonyms: atomic_number_1 H
Related terms: gas chemical_element tritium water
Similar spelling:   hydrogenate
  hydrogel
  hydrozoan
  hydroxide
  hydrocele
  hydroxy
  hydrous
  hydrography
  Hydrozoa
  hydroxyzine
  hydroxyl