What does diacist mean?

"Diacist" is not a common word in English and doesn't have a widely recognized meaning. It's possible you might have encountered a misspelling or a word from a specific technical field.

Here are some possibilities:

* Typo: It could be a misspelling of a similar word, such as "diacritic" or "diagnostician."

* Technical Term: It may be a term used in a specialized field like linguistics or computer science.

If you can provide more context, such as where you encountered the word, I may be able to give you a more specific answer.