一丁
いっちょう one leaf (of a book bound in Japanese style)
Why it means this
一 (one) + 丁 (a counter for blocks, portions, tools) — one block of tofu, one order of a dish, one leaf of a book; also 一丁やるか, 'right, let's have a go'.
Breakdown
Each character links to its full entry — origin story, stroke order, and readings.