In Microsoft Word, single spacing refers to the format setting that allows one line of space between each line of text. To single space an entire document, you can select the top of the document, go to Design > Paragraph Spacing, and choose No Paragraph Space. To single space a portion of the document, you can select the paragraphs you want to change, go to Home > Line and Paragraph Spacing, and choose 1.0. Alternatively, you can right-click on the paragraph you want to single space, select Paragraph, go to the Indents and Spacing tab, and set the Line Spacing option to Single. The default spacing in Word is 1.08 lines, which is slightly larger than single spaced.