o

/ou/

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The word "O" has a few different meanings, and I will explain them clearly for you.

Basic Definition:

1. Blood Type: "O" refers to a blood group. People with type O blood have red blood cells that do not have A or B antigens. Because of this, individuals with type O blood can donate blood to anyone, making them "universal donors."

2. Letter: "O" is the 15th letter of the Roman alphabet. It is a vowel.

3. Element: In chemistry, "O" stands for oxygen, a nonmetallic element that is essential for life on Earth. Oxygen is a colorless, odorless gas that makes up about 21% of the Earth's atmosphere.

Advanced Usage:

• In scientific contexts, "O" is used to represent oxygen in chemical formulas, such as H2O (water) and CO2 (carbon dioxide).
• In blood donation contexts, "O" can be used with a plus or minus sign, like O+ or O-, to indicate the Rh factor (another blood group classification).

Word Variants:

• Blood Type Variants: O+ (positive) and O- (negative) are variants of type O blood.
• Chemical Symbol: "O" is the symbol for oxygen in the periodic table.

Different Meanings:

• As mentioned, "O" can refer to blood type, a letter, or the element oxygen. Each context gives it a different meaning.

Synonyms:

• For the blood group: "Universal donor" (although this phrase refers to the function of type O blood, not a synonym for the letter itself).
• For the letter: There are no direct synonyms for letters, but it is one of the vowels (A, E, I, O, U).

Idioms and Phrasal Verbs:

• There are no specific idioms or phrasal verbs that use just "O," but you might find expressions that include the letter, such as:
  • "Oh no!" – An expression of surprise or dismay.
  • "O my!" – An expression of astonishment or amazement.

Academic

Noun

1. the blood group whose red cells carry neither the A nor B antigens
   • people with type O blood are universal donors
2. the 15th letter of the Roman alphabet
3. a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust

Synonyms

• O
• type O
• group O
• oxygen
• atomic number 8