まぐろ

In a sentence

• 寿司屋で美味しいまぐろを食べました。

  I ate delicious tuna at the sushi restaurant.

  Here, 'まぐろ' refers to the food item, tuna, commonly served as sushi or sashimi in Japanese cuisine.

• その漁師は毎日まぐろを探しに出かけます。

  That fisherman goes out every day to look for tuna.

  In this sentence, 'まぐろ' refers to the live tuna fish caught in fishing.

• 彼の話にはいつもまぐろの部分があるようだ。

  It seems his stories always have a boring part.

  This usage of 'まぐろ' is metaphorical, where it implies something dull or monotonous, derived from the tuna's common representation in sushi preparations.