'Tomato' is Nahuatl 'tomatl' (swelling fruit) — the Aztec word originally meant tomatillo, not the red fruit.
A glossy red or yellow edible fruit eaten as a vegetable or in salads, originally from the Americas.
From Spanish 'tomate,' from Nahuatl 'tomatl' (the swelling fruit), from 'tomāhua' (to swell, to become fat). The Aztecs distinguished several varieties: the large red fruit they called 'xītomatl' (navel tomato), while 'tomatl' alone referred to the smaller green tomatillo. Spanish borrowed the generic 'tomatl' but applied it to the large red fruit. The French name 'pomme d'amour' (love apple) arose from a folk etymology or from Italian 'pomo d'oro' (golden apple, referring to yellow varieties). Key roots: tomatl (Nahuatl: "swelling fruit (tomatillo)"), tomāhua (Nahuatl: "to swell, fatten").
The Nahuatl word 'tomatl' actually referred to the tomatillo (the small green fruit in a papery husk), not the red tomato. The Aztecs called the big red fruit 'xītomatl' (navel tomato). The Spanish borrowed the wrong name — or rather, the general name — and applied it to the wrong fruit. Italian 'pomodoro' (golden apple) suggests the first tomatoes to reach Europe were yellow, not red.