First-class; top-notch; of the highest quality or ranking.
あの店は料理が一流で、値段に見合ったサービスが受けられる。
That restaurant is top-class; you get service that matches the price.
彼は一流のピアニストとして世界中で演奏している。
He performs around the world as a first-rate pianist.
一流企業で働くことは多くの人の目標だ。
Working at a top company is the goal of many people.
Characteristic of; peculiar to — indicating something typical or distinctive of a group or type.
彼の作品には一流の職人技が感じられる。
One can sense craftsmanship characteristic of a master in his work.
一流のサービス精神があれば、客の小さな要望にも応えられる。
With a first-class service attitude, you can respond to customers' small requests.
Can mean a school or faction (e.g., of traditional arts or styles), referring to one specific school.
彼は昔ながらの一流に師事している生け花家だ。
He is an ikebana artist apprenticed to an old-established school.
An archaic meaning referring to a single banner or streamer (also written 一旒); rare in modern usage.
古文書には一流の旗が描かれているが、現代ではほとんど見られない表現だ。
Old documents depict a single banner (一流), an expression rarely seen today.