noun which may take the genitive case particle 'no', noun
first-class; first-rate; top-grade
Used to describe something of the highest quality, rank, or importance. Often appears in formal or evaluative contexts.
彼は第一級の料理人だ。
He is a first-class chef.
このホテルは第一級のサービスを提供している。
This hotel provides first-rate service.
一流 also means first-class or top-notch, but is more commonly used for people, schools, or abstract qualities, while 第一級 can emphasize a formal rank or grade.
最高級 means highest grade or top quality, often used for products or luxury items, and carries a stronger nuance of 'ultimate' compared to 第一級.
Compound of 第 (ordinal prefix), 一 (one), and 級 (class, rank). The reading だいいっきゅう reflects the standard pronunciation of 第一 (だいいち) + 級 (きゅう) with gemination.