noun
canned tuna; tinned tuna
Originally a brand name (Sea Chicken) that became a generic term for canned tuna in Japanese. Used in everyday contexts.
from English Sea Chicken
サラダにシーチキンを入れるとおいしい。
It's delicious when you add canned tuna to a salad.
スーパーでシーチキンを買ってきた。
I bought some canned tuna at the supermarket.
Hyphenated variant, rarely seen in practice.
ツナ is a more direct loanword for tuna, often used for fresh or cooked tuna, while シーチキン specifically refers to canned tuna and carries the brand-name origin.
From the English brand name 'Sea Chicken', originally a trademark for canned tuna. The exact derivation is uncertain, but it became a genericized term in Japanese.