noun
definitive edition; authoritative recording
Used for a recording or album that is considered the best or most representative version of a work, often a remastered or specially selected collection.
See also: 盤
このアルバムは彼の代表作の決定盤と言われている。
This album is said to be the definitive edition of his representative works.
クラシック音楽の決定盤を集めるのが趣味です。
My hobby is collecting definitive recordings of classical music.
完全盤 means a complete recording, often containing all tracks or uncut versions, whereas 決定盤 focuses on being the best or most representative.
Compound of 決定 (decision, definitive) and 盤 (record, disc). The exact origin is uncertain, but it likely arose in music journalism to denote a recording that settles which version is the best.