one edition; first edition
Refers to a single edition or printing of a publication. Often used in contexts like 'first edition' (初版) but can also mean 'one edition' in a series.
The first edition of this book is very valuable.
The print run per edition is small.
Compound of 一 (one) and 版 (edition, printing). The reading いっぱん follows regular rendaku voicing of はん to ぱん after 一.