A family of Microsoft word processing software products for creating web, email, and print documents.
A paragraph style defines a collection of character and paragraph properties (such as font name, font size, line spacing etc.) that you can apply in one step. A character style includes only character formatting (font, font size, etc.).
Note that Word supports other types of styles as well, but only the two types mentioned above can be included in a style set.
A style set is the collection of paragraph and character styles currently available in the gallery at the Home tab. You can switch to a different style set on the Design tab in Word. See also https://support.office.com/en-us/article/choose-a-quick-style-set-for-a-document-a1f3cd51-9cd8-400d-9082-d96b1ee6eb9c.