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

Quick pickled cucumbers, dressed with rice vinegar, sugar and sesame oil, bring texture and acidity while a classic Mexican mix of minced onion and cilantro finishes things off.

From The Wall Street Journal • Apr. 6, 2026

"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

"Our results revealed differences in acidity of the biofilms, with the ones treated with arginine being significantly more protected against acidification caused by sugar metabolism" says the first author, Yumi C. Del Rey.

From Science Daily • Jan. 9, 2026

I was planning on assessing the acidity of the soil in my garden for the rest of the week.

From "Counting by 7s" by Holly Goldberg Sloan