devotion

(noun) feelings of ardent love. Synonyms: devotedness. Example: "Their devotion to each other was beautiful."

(noun) commitment to some purpose. Example: "The devotion of his time and wealth to science."

(noun) religious zeal; the willingness to serve God. Synonyms: idolatry, veneration, cultism.

(noun) (usually plural) religious observance or prayers (usually spoken silently). Example: "He returned to his devotions."