Confirmation
Middle English: via Old French from Latin confirmatio(n- ), from confirmare ‘make firm, establish’ (see confirm).
wiktionary
From Middle English confirmacioun, from Old French confirmacion, from Latin cōnfirmātiō, noun of process from cōnfirmātus(“confirmed”), perfect passive participle of cōnfirmāre, from con-(“with”) + firmāre(“to firm or strengthen”).
Morphologically confirm + -ation.
etymonline
confirmation (n.)
c. 1300, confyrmacyoun, the rite whereby baptized persons are admitted to full communion with the Church, from Old French confirmacion (13c.) "strengthening, confirmation; proof; ratification," and directly from Latin confirmationem (nominative confirmatio) "a securing, establishing; an assurance, encouragement," noun of action from past-participle stem of confirmare (see confirm).
Meaning "verification, proof, supporting evidence" is from late 14c. Meaning "act of rendering valid by formal assent of authority" is from c. 1400; sense of "action of making sure, a rendering certain or proving to be true" from early 15c.
