Refers to tuna as a food ingredient, commonly canned tuna used in salads, sandwiches, and onigiri. Not typically used for the live fish.
I put tuna on the toast and baked it.
I opened a can of tuna and made a salad.
This rice ball has tuna mayo in it.
I mixed the tuna with mayonnaise to use as a sandwich filling.
tuna sandwich
light canned tuna
tuna mayonnaise; tuna mayo
Loanword from English 'tuna'.