reconstruction vs mending

reconstruction and mending both are nouns.

Word	Noun	Adjective	Verb	Adverb
reconstruction	Yes	No	No	No
mending	Yes	No	No	No

As nouns, mending is a hypernym of reconstruction; that is, mending is a word with a broader meaning than reconstruction:

Other hypernyms of reconstruction include fix, fixing, fixture, mend, repair, reparation.

reconstruction (noun)	mending (noun)
the activity of constructing something again	the act of putting something in working order again
recall that is hypothesized to work by storing abstract features which are then used to construct the memory during recall	garments that must be repaired
an interpretation formed by piecing together bits of evidence