Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
indention is a noun meaning "the space left between the margin and the start of an indented line". It carries one recorded sense.
the space left between the margin and the start of an indented line
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 indention come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.