What is the meaning of Aztec word tomato?

The word "tomato" doesn't actually come from an Aztec word. It's a corruption of the Nahuatl word tomatl, which means "plump fruit".

The Nahuatl language was spoken by the Aztecs, but it wasn't the only language in Mesoamerica. The Aztec Empire was actually a multi-lingual one, with many different indigenous languages spoken within its borders.

So, while the tomato is a staple food in Mexican cuisine and is often associated with the Aztecs, the word itself actually comes from the Nahuatl language, which is distinct from Aztec, though closely related.