point

If you can master this, you can become a text layout expert!?

Symbol: pt, ポ / Base data: Size (print).
Unit expressing size of printed characters.1 point = 1/72 inch ≒ 0.3527 mm

Became mainstream after the War

The size of text in a word processor is often expressed in “points”, isn’t it? 1 point is 1/72 of an inch or about 0.35 mm. 10 point is 3.5 mm on all sides and this passage is in 9 point. It started to be used as a unit for printed text after the War in order to gain some kind of layout consistency with overseas documents.