noun
last volume; second volume (of two); third volume (of three)
Refers to the final volume in a set of two or three. In a two-volume set, it is the second; in a three-volume set, it is the third. Often contrasted with 上巻 (first volume) and 中巻 (middle volume).
この小説の下巻は来月発売されます。
The last volume of this novel will be released next month.
上下巻
I ended up reading only the second volume of the two-volume set first.