Definition of Indentation

Noun: indentation  ,in,den'tey-shun

1. A concave cut into a surface or edge (as in a coastline)
   - indenture
    
2. The formation of small pits in a surface as a consequence of corrosion
   - pitting, roughness
    
3. The space left between the margin and the start of an indented line
   - indention, indent, indenture
    
4. The act of cutting into an edge with toothlike notches or angular incisions

See also:
indent
indentations