noun (n)

• a concave cut into a surface or edge (as in a coastline)(noun.shape)

  Synonym:
  indenture
  

  source: wordnet30
• the formation of small pits in a surface as a consequence of corrosion(noun.process)

  Synonym:
  pitting, roughness
  

  source: wordnet30
• the space left between the margin and the start of an indented line(noun.communication)

  Synonym:
  indent, indention, indenture
  

  source: wordnet30
• the act of cutting into an edge with toothlike notches or angular incisions(noun.act)

  source: wordnet30
• The act of indenting or state of being indented.(noun)

  source: webster1913