noun
number of characters per line, page, etc.
Used in publishing, typesetting, and word processing to specify character count per line or page. Often appears in compound terms like 40字詰め (40 characters per line).
この原稿は40字詰めで書いてください。
Please write this manuscript with 40 characters per line.
字詰めを変更すると、レイアウトが崩れることがある。
Changing the character count per line can sometimes break the layout.
行数 refers to the number of lines, while 字詰め refers to the number of characters per line or page.
文字数 is a general term for character count, whereas 字詰め specifically refers to the set number of characters per line or page in a layout.
Compound of 字 (character) and 詰め (packing, filling), from the verb 詰める (to pack, to fill). The term literally means 'character packing' and refers to how many characters are packed into a line or page.