vagón
ES [baˈɣon] · Spanish for “railway carriage” · matches Czech vagon (also a carriage)
The first Spanish word I understood without anybody teaching it to me was printed on a Renfe ticket somewhere south of Madrid: vagón. Czech has vagon, one accent away, and it means precisely the same thing - the carriage you happen to be sitting in. I felt mildly cheated. You spend months being told that nothing carries over between languages and then a railway company hands you one for free.
The catch sits in the mouth rather than on the page. A Spanish v leans towards a b, so what comes out of the loudspeaker is closer to bagón, and it took me an embarrassing while to match the announcement to the word printed on my own ticket.
Neither language invented it. English wagon was a fifteenth-century pickup from Dutch, and once railways existed the word rolled back across the Channel - French took wagon and German took Waggon. Spanish got vagón from the French side and Czech got vagon through the German one. The deeper history is what makes it a homecoming rather than a plain loan. Latin vehiculum, German Wagen, Czech vůz and English wain all grew out of one Indo-European root for carrying and going by vehicle. So Spanish already owned vehículo and Czech already owned vůz long before a train existed anywhere. What turned up in the nineteenth century was a distant relative of both, back home in English spelling with a railway attached.