excellence (n.)youdaoicibaDictYouDict
mid-14c., from Old French excellence, from Latin excellentia "superiority, excellence," from excellentem (nominative excellens) "towering, distinguished, superior" (see excellent).
excellency (n.)youdaoicibaDictYouDict
"high rank," c. 1200, from Latin excellentia "superiority, excellence," from excellentem (see excellent); as a title of honor it dates from early 14c.
par excellenceyoudaoicibaDictYouDict
French, from Latin per excellentiam "by the way of excellence." From French par "by way of, by means of," from Latin per (see per). For second element see excellence.