1590s, "act of putting in," from French insertion (16c.) or directly from Late Latin insertionem (nominative insertio) "a putting in," noun of action from past participle stem of Latin inserere "to graft, implant" (see insert (v.)). Meaning "that which is inserted" attested from 1620s.
with many insertions in the margins
insensitive
insensuous
inseparability
inseparable
insert
insertion
in-service
inset
inshallah
inshore
inside