False friend is the linguistic term for a word in another language that looks just like a word in your own, and so you assume it means the same thing. Be careful! It's wonderful to make friends of new words, but make sure you really know them, or they'll only hurt you.
English has very many words that were borrowed from French, or that English and French both took from Latin, which have kept the same meaning: préparation, longue, noble, thème, champion, etc.
For future reference, if you're ever in southern France and you need new batteries for your camera, it is better not to go into a store asking for "Les batteries." The better word here is piles.
Une batterie is a drumset.