a. A bulbous plant (Allium cepa) cultivated worldwide as a vegetable.
b. The rounded edible bulb of this plant, composed of fleshy, tight, concentric leaf bases having a pungent odor and taste.
2. Any of several other plants in the genus Allium.
[Middle English oynoun, unyon, from Anglo-Norman oignon, ongnon, from Vulgar Latin *uniō, uniōn-, variant of Latin ūniō, ūniōn- length of the initial u uncertain), perhaps from ūnus, one (in reference to the single compact bulb of the onion, as opposed to the multiple cloves of garlic); see oi-no in the Appendix of Indo-European roots, or perhaps akin to Sanskrit uṣnaḥ, onion, Pashto ū&zhookr;a;, garlic, and Hittite wašḫar, -wašḫan- in šuppiwašḫar, onion (šuppi-, pure).]
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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:
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.