a paragraph, section
齣 centers on a distinct unit of text: a paragraph or section that breaks writing into readable parts.
齣 combines 齒 (teeth) with 句 (phrase), likely suggesting a bite-sized piece of text. The exact historical development is uncertain.
The left side 齒 looks like a row of teeth, and the right side 句 suggests a phrase. Imagine biting off a small chunk of text with your teeth: each bite is a paragraph or section.
For シャク, picture a shack where a writer divides a long scroll into sections: shack -> シャク, and each section is a 齣.