binding margin; gutter; seam allowance
Refers to the extra space left along the edge of a page or fabric for binding or sewing. In bookbinding it is the gutter margin; in sewing it is the seam allowance.
When printing, please leave enough binding margin.
This book has a narrow gutter, so it's hard to copy.
Standard kanji spelling for the binding margin or seam allowance.
Kana spelling is sometimes used in instructions or when the kanji 綴 is considered difficult.
Compound of 綴じ (とじ, continuative form of 綴じる 'to bind') + 代 (しろ 'allowance, margin').