Definitions for "Slide Master"
The slide master can be thought of as a layout that contains "how you want the presentation to look". Often the slide master contains the layout, choice of fonts, color, background image and logo. It can also be thought of as the template settings.
The Slide Master is the slide that holds the formatting for the title, the text, and any background items that appear on the slides. Any text styles or graphics that appear on the Slide Master will appear on all of the slides in a presentation.
An overall guide created by PowerPoint for each new presentation that contains formatting features and standard layout characteristics for all slides (except title slides).