INDENTATION
indentation
(noun) the act of cutting into an edge with toothlike notches or angular incisions
indentation, indention, indent, indenture
(noun) the space left between the margin and the start of an indented line
pitting, roughness, indentation
(noun) the formation of small pits in a surface as a consequence of corrosion
indentation, indenture
(noun) a concave cut into a surface or edge (as in a coastline)
Source: WordNet® 3.1
Noun
indentation (countable and uncountable, plural indentations)
The act of indenting or state of being indented.
A notch or recess, in the margin or border of anything
A recess or sharp depression in any surface.
(typography) 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.
A measure of the distance from the flush line
(law) A division unit of a piece of law distinguished by its indentation or by a dash
 Synonym: indent
Antonyms
• protrusion
Source: Wiktionary
In`den*ta"tion, 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.
4. (Print.)
(a) 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.
(b) The measure of the distance; as, an indentation of one em, or of
two ems. Hanging, or Reverse, indentation, indentation of all the
lines of a paragraph except the first, which is a full line.
Source: Webster’s Unabridged Dictionary 1913 Edition