Acid Is Named After Sourness
An acid is a substance that donates protons and tastes sour. The Latin root simply means sharp or sour.
An acid is a substance that donates hydrogen ions in solution, turns litmus red and tastes sour. The name predates the chemistry: Latin *acidus* meant sour, and early chemists classified substances by taste long before they understood why. Sourness is precisely what hydrogen ions register as on the tongue, so the old test was a good one. The same root gives *acute*, *acrid* and *vinegar*, the last from French *vin aigre*, sour wine.
- A sour substance. *A weak acid.*
- pH below 7. *Acidic.*
- Sharp in manner. *An acid remark.*
- Alkali — the opposite. *An alkali.*
- Latin — *acidus*, sour. *The source.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | acid | An acid. |
| Plural | acids | Acids. |
| Adjective | acidic | Acidic. |
| Noun | acidity | Acidity. |
| Latin | acidus | Sour. |
- Lemon juice is a weak acid.Chemistry.
- She made an acid comment.Figurative.
- Acidus meant sour.Etymology.
The acidus family
- Acid — sour
- Acute — sharp, of an angle or a pain
- Acrid — sharp and unpleasant to smell
- Vinegar — from French *vin aigre*, sour wine
- Eager — through French, originally meaning sharp or keen
Latin *acidus*, sour or sharp, from *acere*, to be sour, related to *acer*, sharp.
Why are acids named after taste?
Because early chemists classified them by tasting, long before proton donation was understood. Sourness is exactly what hydrogen ions register as.
Is vinegar related?
Yes, through French vin aigre, sour wine. Aigre comes from the same Latin root as acid.