noun
line progression; line advance direction
Computing term referring to the direction in which lines of text or data advance, such as in printers or display systems.
このプリンターの行進行方向は左から右です。
The line progression direction of this printer is from left to right.
Compound of 行 (line), 進行 (advance, progress), and 方向 (direction). The exact derivation is uncertain; it appears to be a technical term formed within computing contexts.