What is word for first name in diaries?

There isn't a specific word for a first name in diaries. However, you can use various terms depending on the context:

* Name: This is the most general and straightforward option.

* First name: This is more specific and emphasizes the distinction from a last name.

* Given name: This term is more formal and emphasizes the name given to the person at birth.

* Personal name: This term emphasizes the individual's identity and uniqueness.

* Alias: This term is used if the diarist uses a pseudonym.

Ultimately, the best word to use depends on the specific context and the style of writing.