HOW TO USE THE DICTIONARY

To look up an entry in The American Heritage Dictionary of the English Language, use the search window above. For best results, after typing in the word, click on the “Search” button instead of using the “enter” key.

Some compound words (like bus rapid transit, dog whistle, or identity theft) don’t appear on the drop-down list when you type them in the search bar. For best results with compound words, place a quotation mark before the compound word in the search window.

guide to the dictionary

kid·ney

(kĭdnē)

n. pl. kid·neys

1. Anatomy Either one of a pair of organs in the dorsal region of the vertebrate abdominal cavity, functioning to maintain proper water and electrolyte balance, regulate acid-base concentration, and filter the blood of metabolic wastes, which are then excreted as urine.

2. The kidney of certain animals, eaten as food.

3. An excretory organ of certain invertebrates.

4. Temperament; kind: a person of the same kidney.

[Later Middle English kideney, possibly back-formation (on the model of Middle English ey, egg, and its usual plural eiren, eggs, probably influenced by the similarity of the rounded shape of kidneys to that of eggs) from Middle English kideneiren, plural of kideneire, kidney : kide-, perhaps meaning “belly” or “pod, capsule” (in reference to the renal capsule, a tough fibrous membrane surrounding the kidney and surrounded by a layer of fat; compare Modern English dialectal (southern England) kid, pod, peasecod, probably from Old English *cyde, and akin to Old English codd, bag, sack, peasecod) + neire, kidney (from Old English *nēore, from Germanic *neurōn-; akin to Greek nephros, kidney, and Latin (colloquial dialect of the ancient city of Praeneste, east of Rome) nefrōnēs, testicles).]

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

American Heritage Dictionary Products

HOW TO USE THE DICTIONARY

THE USAGE PANEL

AMERICAN HERITAGE DICTIONARY APP

THE AMERICAN HERITAGE DICTIONARY BLOG

INTERESTED IN DICTIONARIES?

Indo-European & Semitic Roots Appendices

American Heritage Dictionary Products