Double spacing in Word refers to the act of adding a blank line between every line of text, which makes the document easier to read and has more space for notes or comments. Here are some ways to double space in Word:

• Double space the whole document: Go to the Design tab, click on Paragraph Spacing, and choose Double.
• Double space selected text: Select the text you want to double space, go to the Home tab, click on Line and Paragraph Spacing, and choose 2.0.
• Change line spacing: Select the paragraph or paragraphs you want to adjust, click on the Line and Paragraph Spacing button, and select a spacing option. For more spacing options, select Line Spacing Options to open the Paragraph dialog box.
• Change paragraph spacing: Click on the Paragraph dialog box launcher, adjust the settings in the Spacing group, and click OK. Additional space will be added before or after the selected paragraph.

Double spacing is commonly used in schoolwork and professional settings, and is a standard part of several grammar style books such as APA, Chicago, MLA, and more.