ツナ

ツナ refers specifically to canned or processed tuna, not fresh tuna. From English "tuna."

CONTRAST WITH 鮪(まぐろ):

• ツナ: canned/processed tuna — used in sandwiches, salads, and onigiri
• 鮪(まぐろ): fresh tuna — used for sushi, sashimi, and seafood dishes

This distinction is important: you would never call sushi tuna ツナ, and you would not call canned tuna 鮪(まぐろ).

Compounds

• ツナ缶(かん): can of tuna
• ツナサラダ: tuna salad
• ツナサンド: tuna sandwich
• ツナマヨ: tuna mixed with mayonnaise (very popular onigiri filling)

Cultural note

シーチキン (Sea Chicken) is a well-known brand name for canned tuna in Japan, sometimes used generically like "Band-Aid" in English. ツナマヨ is consistently one of the top-selling onigiri flavors in convenience stores.