Is eau masculine or feminine in French?
Eau is feminine: l’eau, une eau. Because it begins with a vowel, the article elides to l’, which hides the gender — but it is definitely feminine. The plural is les eaux (with an -x), as in les eaux usées (waste water). Any adjective must agree in the feminine: une eau fraîche, not un eau frais.
Why is eau feminine when -eau is usually masculine?
The ending -eau is one of the most reliable masculine markers in French: le bateau, le gâteau, le manteau, le tableau are all masculine. Eau is a genuine exception you simply have to memorise. The reason is historical: it descends from the Latin aqua, which was feminine, and it kept that gender even as its spelling and pronunciation changed completely over the centuries. So the suffix rule does not apply here — origin wins. This is a good reminder that suffix rules are reliable guides, not absolute laws, and that a handful of very common words break them.
How do you use eau in a sentence?
Notice how the elided l’ and feminine agreement work together:
Preply
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- L’eau est froide ce matin. (The water is cold this morning.)
- Je voudrais une eau minérale, s’il vous plaît. (I’d like a mineral water, please.)
- Les eaux de la rivière sont montées. (The river waters have risen.)
The mistake learners make with eau
Because l’eau never shows a full le or la, learners assume it follows the -eau masculine pattern and write un eau or eau fréquenté with masculine agreement. Always treat it as feminine: une eau, cette eau, une eau plate. When the article is hidden by elision, the adjective ending is your proof of gender.
When you are unsure of any noun’s gender while writing — in a TCF message, a DELF letter, or everyday French — verify it before you commit it to the page. The French Gender Checker returns the correct article, the plural, and the rule behind the gender for any noun in a single lookup, so a word like eau is never a guess again.
