1. N-VAR Tuna or tuna fish are large fish that live in warm seas and are caught for food. 金槍魚(yú)

...a shoal of tuna. …一群金槍魚(yú)。

2. N-UNCOUNT Tuna or tuna fish is this fish eaten as food. 金槍魚(yú)肉

She began opening a can of tuna. 她開(kāi)始打開(kāi)一罐金槍魚(yú)。

3. N any of various tropical American prickly pear cacti, esp Opuntia tuna, that are cultivated for their sweet edible fruits 刺梨仙人掌(尤指金槍仙人掌)