Benediction, n.
Etymology: [L. benedictio: cf. F. bénédiction. See Benison.]
1. The act of blessing.
2. A blessing; an expression of blessing, prayer, or kind wishes in favor of any person or thing; a solemn or affectionate invocation of happiness. So saying, he arose; whom Adam thus Followed with benediction. Milton. Homeward serenely she walked with God's benediction upon her. Longfellow. Specifically:
The short prayer which closes public worship; as, to give the benediction.
3. (Eccl.)
3 more senses
The form of instituting an abbot, answering to the consecration of a bishop. Ayliffe.
4. (R. C. Ch.)
A solemn rite by which bells, banners, candles, etc., are blessed with holy water, and formally dedicated to God.
Shades of meaning
Fernald lists benediction only as an antonym, under oath.
He lists it without comment; the entries above explain its neighbors.