In typesetting, a strut is an invisible character or element, used to ensure that a text has a minimum height and depth, even if no other elements are included.
For example, LaTeX and plain TeX[1] provide the command \strutto insert a font size-specific strut. In LaTeX[2] it has a height of 70% of the baseline skip (the distance between the baselines of two consecutive lines of text) and a depth of 30% of the baseline skip. It ensures that two vertical stacked boxes which include such a strut have the same distance as two normal consecutive lines. LaTeX also supports the creation of general struts using the command: \rule[-''depth'']
where \strut is equivalent in size to