Definition of H2O in English:

H2O

(also H2O)

noun

mass nouninformal
  • Water (the chemical symbol, as used in non-scientific contexts)

    ‘if you spend a leisurely ten minutes washing and rinsing, you'll be going through gallons of H2O’
    • ‘Tom enjoyed just three frothy pints, and he wisely quaffed a liter of H20 before bed.’
    • ‘A river is more than the sum of the H20 particles which stream between its banks.’
    • ‘It's well-known that sweaty exercise flushes both water and sodium from your system, so to rehydrate, you require more than just H20.’
    • ‘The dishwasher was leaking all to hell and my kitchen was submersed in a good half an inch of concentrated soap and H20.’
    • ‘If you haven't had the sense to drink plenty of water the night before, or better still, alternate a drink of H20 with your favourite tipple, then Mother Nature is your greatest ally.’
    • ‘Should any of these tell-tale signs occur, head indoors or find a shady place to sit, loosen your clothing, dampen a scarf or shirt with cool water and pat yourself down and, of course, keep on drinking the cool, clean H20.’
    • ‘Also, your body will need more water as the mercury rises to stay hydrated, so if you were skimping on the H20 during the winter, make it a goal to drink the suggested eight glasses of water every day.’
    • ‘After this I was breathing pretty hard and struggled to jog home where I downed copius amounts of H20 then headed off to uni.’
    • ‘We've all been told a thousand times, but a lot of us still don't get enough H20 during the day.’
    • ‘Whether it's an extra 30 minutes of sleep a night, taking a trip, learning a foreign language, reading a book or snowboarding down the side of a mountain, be sure to drink plenty of H20 while pursuing fun activities.’

Origin

From H (sense 2 of the symbol), chemical symbol for hydrogen, + 2 + O (symbol), chemical symbol for oxygen.