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. 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. 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.