Skip to main content
Glite Dictionary
🔤 A letter 🩸 A blood group 🧪 Oxygen symbol
O

O

13 1.0
A symbol for oxygen, the colorless gas we breathe
  • noun
  • /oʊ/
  • Specialized
translation icon : oxígeno
  • When we breathe in, we rely on the presence of O in the atmosphere to survive.
  • O bond
  • O bond cleavage
  • O activation

Examples

  • In 1930, he suggested that oxygen molecules (O2) are split by cosmic rays into two oxygen atoms.

    Academic text (1993)

  • Risk of fire is particularly enhanced in oxygen (O2) and nitrous oxide (N2O) enriched atmospheres.

    Academic text (2007)

  • In the laboratory, we monitor the concentration of O in the air, as it is essential for combustion.

  • The chemical formula for water includes O to represent the oxygen atoms in the molecule.

Idioms

uh-oh, Spaghetti-O
  • Baby Talk
9.9

A short phrase showing mild surprise or worry said in a playful way

Compounds

group O
  • Specialized
47 3.7

A blood type with no A or B markers that can be given to most people

Jell-O
46 2.8

A sweet, fruit flavored dessert made from a powder that becomes soft and wobbly

type O
  • Specialized
7 3.9

A blood group whose red cells have no A or B markers, so they can donate to anyone

O-ring
  • Specialized
1 6.1

A round rubber or plastic ring that seals a joint to stop leaks

O level
  • Archaic
1 7.9

A public exam in the UK for secondary students, now replaced by GCSEs

jack-o-lantern
  • Specialized
9.9

A large poisonous mushroom with an orange cap that glows at night

jack-o-lantern fungus
  • US
9.9

A large poisonous mushroom with orange caps that grows in tight groups and gills that glow in the dark

rabbit-o mode
  • Slang
9.9

A state of becoming very jumpy and worried when stressed

penicillin O
  • Specialized
4.6

A medicine made by some mould that kills bacteria and is like penicillin G

smell-o-vision
9.9

A way to make people smell scents while watching films or TV

Surface Forms

O singular
Os plural

Etymology

The chemical symbol O stands for oxygen, a word made from Greek parts that meant 'acid producer' because early scientists thought this gas made acids. Today the single letter O is the short sign we use for that important gas.