本

The character is a simple ideogram.

It shows 木 (나무 목, “tree”) with 一 drawn at the base of the trunk — visually indicating the root of the tree.

This depiction of the tree’s root makes it one of the most frequently cited classic examples of an ideogrammatic character.

Because the root of something represents its origin, 本 came to mean “foundation, origin, the essence.”

Later, it was also used for “book”, because books were seen as containing the “roots” of knowledge.