What is the meaning of Tonno?

Tuna in solid (unflaked) form, packed in olive oil.

tuna, specifically:

  1. any of several species of fish of the genus Thunnus
  2. the edible flesh of the tuna

any of several species of fish of the genus Thunnus

the edible flesh of the tuna

the fish on a fess

fool, dupe

Source: wiktionary.org