Actually, now I come to look at the picture properly, three treats
(excuse me, I'm dribbling as I type).
There is a sort of éclair produced in some parts of the USA which is really a long doughnut filled with vanilla custard, but the original éclair, as shown here, is made with choux pastry and is filled with creamy stuff (perhaps even chestnut puree) and topped with icing.
If it's caramel icing then it's a bâton de Jacob.
The word éclair meaning a sort of cake arrived in English and French in the 1860s, but there are those who credit the very great chef Antonin Carême with its invention, even though he'd been dead thirty years by then.
Apart from cake, Éclair was a French camera firm. Éclair cameras are important, firstly because they developed an instant-change film-magazine system which allowed a freer form of shooting and made possible a new sort of film now called the French New Wave, and secondly because their NPR (Noiseless Portable Reflex) camera proved jolly useful for documentaries such as Woodstock.
Though I would have thought that a bit of extra noise at Woodstock wouldn't have made a lot of difference, myself.
Word To Use Today: éclair. This word is the French for lightning. Whether it's because the cakes only last as long as lightning, or because the idea came like a flash of lightning nobody knows. Before that the word came from the Latin eclārāre, to make bright.