insertion vs enclosure

insertion and enclosure both are nouns.

Word	Noun	Adjective	Verb	Adverb
insertion	Yes	No	No	No
enclosure	Yes	No	No	No

As nouns, enclosure is a hyponym of insertion; that is, enclosure is a word with a more specific, narrower meaning than insertion:

insertion (noun)	enclosure (noun)
the act of putting one thing into another	the act of enclosing something inside something else
a message (spoken or written) that is introduced or inserted	a structure consisting of an area that has been enclosed for some purpose
	something (usually a supporting document) that is enclosed in an envelope with a covering letter
	a naturally enclosed space