indentation

Short definition from Wiktionary

Noun

1. 1
   The act of indenting or state of being indented.
2. 2
   A notch or recess, in the margin or border of anything.
3. 3
   A recess or sharp depression in any surface.
4. 4
   The act of beginning a line or series of lines at a little distance within the flush line of the column or page, as in the common way of beginning the first line of a paragraph.
5. 5
   A measure of the distance from the flush line.
6. 6
   A division unit of a piece of law distinguished by its indentation or by a dash.