noun
big bank; major bank
Refers to a large-scale financial institution, often one of the major banks in Japan or globally.
日本の大銀行は海外にも支店を持っている。
Major Japanese banks have branches overseas as well.
銀行 is the general term for 'bank', while 大銀行 specifically emphasizes a large or major bank.
Compound of 大 (dai, 'big') and 銀行 (ginkō, 'bank').