The amount of blank space between each line of text line spacing

Line spacing determines the amount of vertical space between lines of text in a paragraph.

Explanation:

By default, lines are single-spaced, meaning that the spacing accomodates the largest font in that line, plus a small amount of extra space.

You set line and paragraph spacing on the indents and spacing tab of the paragraph dialog box.

You can also align text to baseline guides to precisely line up text across multiple columns. You set baseline guides on the baseline guides tab of the layouts guides.