devotion n.

active word-forming element in English and in many verbs inherited from French and Latin, from Latin de "down, down from, from, off; concerning" (see de), also used as a prefix in Latin, usually meaning "down, off, away, from among, down from," but also "down to the bottom, totally" hence "completely" (intensive or completive), which is its sense in many English words.

As a Latin prefix it also had the function of undoing or reversing a verb's action, and hence it came to be used as a pure privative — "not, do the opposite of, undo" — which is its primary function as a living prefix in English, as in defrost (1895), defuse (1943), de-escalate (1964), etc. In some cases, a reduced form of dis-.

"solemn promise," c. 1300, from Anglo-French and Old French voe (Modern French vœu), from Latin votum "a promise to a god, solemn pledge, dedication; that which is promised; a wish, desire, longing, prayer," noun use of neuter of votus, past participle of vovere "to promise solemnly, pledge, dedicate, vow," from PIE root *wegwh- "to speak solemnly, vow, preach" (source also of Sanskrit vaghat- "one who offers a sacrifice;" Greek eukhe "vow, wish," eukhomai "I pray"). The meaning "solemn engagement to devote oneself to a religious order or life" is from c. 1400; earlier "to bind oneself" to chastity (early 14c.).