acidity

American  

[uh-sid-i-tee] / əˈsɪd ɪ ti /

noun

1. the quality or state of being acid.

2. sourness; tartness.

3. excessive acid quality, as of the gastric juice.

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acidity British  

/ əˈsɪdɪtɪ /

noun

1. the quality or state of being acid

2. the amount of acid present in a solution, often expressed in terms of pH

3. another name for hyperacidity

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Other Word Forms

• nonacidity noun
• overacidity noun
• preacidity noun
• superacidity noun

Etymology

Origin of acidity

From the Late Latin word aciditās, dating back to 1610–20. See acid, -ity

Explanation

Acidity is sourness, so you might turn down a bite of your friend's kumquat because its acidity is just too much for you. This noun is good for literal acidity, like a lemon's sour flavor or, in scientific terms, the chemical quality of a substance that reacts with a base to make salt. You can also use it in a figurative way when someone's tone is sharp and biting: "The acidity in my dad's voice told me we were really in trouble for eating all the tomatoes in his garden."

Example Sentences

"Now, there are some good ones, but the majority are still lacking structure, the tannins, the balanced acidity, the complexity," he added.

From Barron's • Feb. 12, 2026

Geoengineering experiments to reduce the Earth’s temperature with aerosols and modify ocean acidity are gathering pace.

From The Wall Street Journal • Jan. 16, 2026

To measure acidity inside the biofilms, researchers used a pH-sensitive dye known as "C-SNARF-4."

From Science Daily • Jan. 9, 2026

Some pharmacies can produce the drug in-house, known as compounding, but the consistency varies and the acidity causes eyes to sting.

From The Wall Street Journal • Dec. 28, 2025

The trees were carnivorous too, but at a much lower level of acidity, safe enough to stay in for the night while the rest of the island seethed.

From "Life of Pi" by Yann Martel