main work and its supplement; original and continuation
Refers to a pair consisting of a primary book or document and its supplementary volume or sequel. Often used in bibliographic or academic contexts.
This series consists of 12 volumes in total, including the main work and its supplement.
It is necessary to consult both the original and the continuation.
Compound of 正 (main, original) and 続 (continuation, supplement). The exact historical derivation is uncertain, but the meaning is transparent from its components.