mermelada
ES [meɾmeˈlaða] ~ CS marmeláda · both “jam, marmalade”
Mermelada in Spanish and marmeláda in Czech both mean jam. For once the look-alike is telling the truth: these aren’t two words that happened to collide, they’re one word wearing two spellings.
This one is a loanword that toured Europe. Spanish mermelada, Czech marmeláda, German Marmelade and English marmalade were all borrowed from Portuguese marmelada, which meant jam made from quince - the marmelo. Follow marmelo back and it opens up: Latin melimelum, from Greek melimelon, a “honey apple.” So a jar of mermelada and a jar of marmeláda hold the very same word, carried out of Portugal with an ancient honey apple sealed at the bottom. English is the odd one out - it quietly reassigned the word to oranges.