oxygen

/ˈɑksɪdʒən/
noun
  1. A colorless, odorless gas that is essential for most living things to breathe and for fire to burn.
    • Firefighters wear tanks of oxygen to breathe in smoky buildings.
    • The hiker struggled to breathe in the thin air, which had less oxygen.
    • Plants produce oxygen during photosynthesis.
  2. Oxygen gas used in medical treatment to help patients breathe more easily.
    • The patient was given extra oxygen through a mask.
    • The ambulance carried portable oxygen tanks for emergencies.
    • She needed oxygen therapy after her lung infection.
Synonyms
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