devotion (n.) Look up devotion at Dictionary.com
early 13c., from Old French devocion "devotion, piety," from Latin devotionem (nominative devotio), noun of action from past participle stem of devovere "dedicate by a vow, sacrifice oneself, promise solemnly," from de- "down, away" (see de-) + vovere "to vow," from votum "vow" (see vow (n.)).

In ancient Latin, "act of consecrating by a vow," also "loyalty, fealty, allegiance;" in Church Latin, "devotion to God, piety." This was the original sense in English; the etymological sense, including secular situations, returned 16c. via Italian and French.