complete set; all volumes
Refers to the entire collection of volumes in a series, often used when buying, owning, or reading the whole set.
この漫画の全巻を集めるのに3年かかった。
It took three years to collect all the volumes of this manga.
He read the complete set of that manga series.
全巻セットで買うとお得です。
It's a good deal if you buy the complete set.
whole volume; entire film
Used for a single volume, film, or reel in its entirety, often in contexts like reading or watching from start to finish.
昨夜、その映画を全巻一気に見た。
Last night I watched the whole film in one go.
この辞書は全巻で約2000ページある。
This dictionary has about 2000 pages in the whole volume.
念願だったそのシリーズの全巻をそろえた。
I finally collected the complete set of that series I had wanted for so long.
I bought the whole set during the sale.
She watched the entire film in one sitting.
全巻 specifically means all the volumes of a multi-volume set, while 全編 refers to the entire single work regardless of how many volumes it has.
全巻 (the complete set of volumes) and 前巻 (the previous volume) share the same reading ぜんかん but mean very different things.
全巻 (all volumes of a series) and 全館 (the whole building, e.g. of a hotel or museum) sound identical but refer to completely different things.
Compound of 全 (zen, 'all, whole') and 巻 (kan, 'volume, reel'). The meaning follows directly from the kanji.