What does this symbol in ancient books mean?

In ancient books, individually framed words are usually used to express important content or special purposes. These framed words are sometimes distinguished by different colors, strokes, and shapes so that readers can identify them more easily. This method can remind readers to pay attention to these words and sometimes help readers better understand the meaning of the text.

In ancient books, octagonal borders were often used to mark important excerpts, quotations, or key points. These contents may be scriptures, poems, aphorisms, etc. related to the theme. Emphasizing these elements with an octagonal border can make them more noticeable to the reader and leave a stronger impression on the reader's memory. At the same time, this kind of frame also has a certain decorative effect and can make the page more beautiful.