H₂O

H₂O

1. Water, by its molecular formula, although rarely pure.
2. (chemistry) A molecule of water.
3. (inorganic chemistry) light water, consisting of two protium isotope of hydrogen atoms and one oxygen atom

• H₃O⁺, H₃O, hydronium
• OH^-, OH, hydroxide
• 2H₂O, H₄O₂, H₃OOH, H₃O-OH, hydronium hydroxide

• D₂O, heavy water
• DHO, semi-heavy water

• deuterium
• DHMO, dihydrogen monoxide
• H₂O₂, hydrogen peroxide

• (US) IPA^(key): /ˌeɪtʃtuːˈoʊ/

H₂O (uncountable)

1. Water as a chemical substance.
   • 1992, John R. Searle, The Rediscovery of the Mind, →ISBN, page 157:

     A man may believe, for example, that the star in the sky is the Morning Star without believing that it is the Evening Star. A man may, for example, want to drink a glass of water without wanting to drink a glass of H₂O.

• OH, oh