What do you call a pronounceable name comprising initial letters?

There isn't a single, universally accepted term for a pronounceable name made up of initial letters. However, here are some options you could use, depending on the context:

Formal:

* Acronym: This is the most common and widely understood term, particularly if the initials form a new word.

* Initialism: This term is used when the initials are pronounced individually rather than as a word.

Informal:

* Letter name: This is a simple and descriptive option.

* Initials name: This is another straightforward option, especially if you want to emphasize the initial letter aspect.

* Nickname: This can be appropriate if the initial name is used informally and affectionately.

Example:

* NASA is an acronym for "National Aeronautics and Space Administration."

* FBI is an initialism for "Federal Bureau of Investigation."

* J.K. Rowling is a letter name often used informally.

* C.S. Lewis is an initials name frequently used in scholarly contexts.

Ultimately, the best term will depend on the specific situation and the tone you want to convey.