say it: in-den-TAY-shuhn
indentation is a noun meaning "a concave cut into a surface or edge (as in a coastline)". It carries 4 recorded senses.
a concave cut into a surface or edge (as in a coastline)
the formation of small pits in a surface as a consequence of corrosion
the act of cutting into an edge with toothlike notches or angular incisions
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for indentation come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.