"Diarist" Natural Recordings by Native Speakers
A diarist is a person who keeps a diary, a daily record of thoughts, events, and feelings. It can also refer to a writer who maintains a diary, often sharing their innermost thoughts and reflections with the public.
A diapositive refers to a transparency or slide used in a slide projector or overhead projector. It is typically a large, mounted transparent sheet bearing a transparency of a diagram, drawing, or photograph, used for educational or presentational purposes.