noun
Refers specifically to Thunnus orientalis, the highly prized Pacific bluefin tuna, often distinguished from other tuna species in culinary contexts.
See also: クロマグロ
本マグロの大トロは最高だ。
The fatty belly of Pacific bluefin tuna is the best.
この寿司屋では本マグロだけを使っている。
This sushi restaurant uses only Pacific bluefin tuna.
本 (hon, 'true' or 'genuine') + マグロ (maguro, 'tuna'), distinguishing the highly valued Pacific bluefin from other tunas.