"The action, state, or fact of adhering to a person or thing; especially steadfast support, allegiance. Also occasionally: an instance of this", Late 16th cent.; earliest use found in Geoffrey Fenton (c1539–1608), translator and administrator in Ireland. From post-classical Latin adhaerentia adherence; compare -y, -ency. Compare earlier adherent.[adherency etymology, adherency origin, 英语词源]