口

1. Origins, structure, and basic meaning

• Structure: 口, read くち, denotes a person’s mouth or an open part of an object such as a bag or container.
• Basic usage: It names a person’s mouth and the open top of a bag tied with string.

2. Common pitfalls and similar expressions

• Mouth and opening
  • The sense extends from a person’s mouth to an opening through which things enter or leave a container.