A reference manual is a document that explains the parts of a product. A reference manual answers the question, "What is x?"
Usually, a reference manual for software has the following features:
- Necessary background information and theory about the subject
- Full information about the product
- An explanation of each dialog box, screen, field, tab, and button
- An explanation of all the options that users have.
Frequently, reference manuals are supplied as online documentation.