件名

1. Origins, structure, and basic meaning

• Structure: The document and email noun 件名 (けんめい) denotes a subject heading, especially an email subject line.
• Basic usage: A date may be placed 件名に, and the message body is opened when 件名だけ is not informative enough.

2. Common pitfalls and similar expressions

• The subject line of a message
  • It is the short title used to identify a message, not the message body; in email it corresponds to the subject line.