whey

American  

[hwey, wey] / ʰweɪ, weɪ /

noun

1. a milk serum, separating as liquid from the curd after coagulation, as in cheesemaking.

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whey British  

/ weɪ /

noun

1. the watery liquid that separates from the curd when the milk is clotted, as in making cheese

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Other Word Forms

• wheyey
  adjective
• wheylike
  adjective

Etymology

Origin of whey

First recorded before 900; Middle English whei(e), whai(e), wei, Old English hwæg, hwæig, hwǣg, hweg; cognate with Dutch, Low German wei

Explanation

Whey is what's left over after you've made cheese by straining curds. Rather than being thrown away, whey is often used to add buttery flavor or extra protein to processed foods. You may know the word whey from the nursery rhyme that begins "Little Miss Muffet sat on her tuffet eating her curds and whey..." Curds and whey are part of the cheese-making process, with whey being the slightly sour leftover liquid. Think buttermilk or thin yogurt, and you've got an idea of what whey tastes like. It's actually a great source of protein and often shows up in healthy smoothies and shakes.

Example Sentences

Whey protein is a billion-dollar sector that continues to grow.

From BBC • Oct. 6, 2025

Whey was considered a healthful drink, a digestive aid family members drank on its own.

From Seattle Times • Jan. 30, 2024

Whey, one of the primary proteins found in milk, may trigger serious or life-threatening allergic reactions in individuals who are either allergic or sensitive to dairy.

From Salon • Jul. 7, 2022

Manhattan is known as Whyt Whey, a reference to Broadway’s White Way.

From New York Times • Dec. 23, 2018

Whey, hwā, n. the watery part of milk, separated from the curd, esp. in making cheese.—adjs.

From Chambers's Twentieth Century Dictionary (part 4 of 4: S-Z and supplements) by Various