‑eaux is the standard French language plural form of nouns ending in ‑eau, e.g. eau → eaux, château → châteaux, gâteau → gâteaux.
In the United States, it often occurs as the ending of Cajun surnames, as well as a replacement for the long "O" (/oʊ/) sound in some English words as a marker of Cajun, or more broadly Louisiana, identity.[1]