also: おおとろ
fatty belly of tuna; high-quality tuna belly
Refers specifically to the very fatty, marbled cut from the belly of a tuna, prized in sushi and sashimi.
The fatty tuna belly at this sushi restaurant is melt-in-your-mouth delicious.
Hiragana variant, less common but still encountered.
From 大 (おお, 'big') + トロ, a term for fatty tuna belly. The origin of トロ is uncertain, but it may be related to the onomatopoeic とろり (thick, syrupy) describing the melting texture.