The story
Named in the Anglophone world for the early origins, in French vinaigrettes, that inspired later versions, although the present-day conventions for the dressing's composition do not directly reflect the original French influence; more at Wikipedia. Compare French fries regarding the name mostly not reflecting any direct French influence.
First known use, by meaning
- From the 1950s A salad dressing that is a uniform viscous sauce with a tangy sweet flavor. It is generally made from vegetable oil, vinegar, ketchup (or tomato puree), water, paprika, other spices, and sweeteners.
Etymology from Wiktionary, CC BY-SA 4.0.