Indentation

n.
  1. The act of indenting or state of being indented.
  2. A notch or recess, in the margin or border of anything; as, the indentations of a leaf, of the coast, etc.
  3. A recess or sharp depression in any surface.
    1. 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.
    2. The measure of the distance; as, an indentation of one em, or of two ems.
    Hanging indentation, or Reverse indentation ,
    indentation of all the lines of a paragraph except the first, which is a full line; also called a hanging indent.