5:4 aspect ratio
A 5:4 display shows 5 units of width for every 4 units of height — 1.25:1 in decimal form. Content mastered for 16:9 will show bars or crop on this shape.
A quirk of the early LCD era: 17- and 19-inch office monitors standardized on 1280×1024, which is slightly taller than 4:3. The near-square shape was good for documents and CAD drawings, and its fleet lives on in point-of-sale terminals, control rooms, and security desks — anywhere hardware gets replaced only when it dies.