縦長

1. Origins, structure, and basic meaning

• Structure: 縦長 (たてなが) describes a vertically elongated or long, narrow shape.
• Basic usage: 縦長の紙 describes page proportions; 縦長の形をしている describes a room extending deep inward.

2. Common pitfalls and similar expressions

• Page proportion and room layout
  • Both use の, but one concerns a flat sheet's orientation and the other a spatial floor-plan shape.