indentation vs indention

indentation and indention both are nouns.

Word	Noun	Adjective	Verb	Adverb
indentation	Yes	No	No	No
indention	Yes	No	No	No

As nouns, indentation and indention are synonyms defined as:

indentation and indention: the space left between the margin and the start of an indented line

Other synonyms of indentation include indent, indenture.

indentation (noun)	indention (noun)
the act of cutting into an edge with toothlike notches or angular incisions	the space left between the margin and the start of an indented line
the space left between the margin and the start of an indented line
the formation of small pits in a surface as a consequence of corrosion
a concave cut into a surface or edge (as in a coastline)