cartón
/kaɾˈton/ · B2 · noun · m
cardboard
📦 cartón = carta (paper/card) + -ón (big): a big, thick card
Spanish carta, 'card/paper', plus the augmentative suffix -ón, meaning 'big'. So cartón is 'big card', which is thick card stock: cardboard. English carton comes from the same source.