O

Options dialog
Dialog: Options - General tabA dialog which contains settings that control how PowerPoint behaves.
 
orientation
The paper we normally print on is rectangular, so you have the choice of printing in Landscape (horizontal) orientation Landscape orientation (horizontal) or in Portrait (vertical) orientationPortrait orientation (vertical).
outline
Outline of a presentationAn outline arranges the thoughts in your document in a hierarchy order where the most important points are at the same outline level and the supporting points are at a lower level. In a PowerPoint presentation, the slide titles are at the highest level in the outline. The bullet points fall in levels below, based on their indentions.
 
outline levels
The hierarchy levels in an outline.
overhead
Short for overhead transparency, a plastic sheet used with an overhead projector to project onto a screen what you have written or drawn on the plastic sheet. PowerPoint can print transparencies, if your printer can handle them.