1. (noun)Sacrament the oath of allegiance taken by Roman soldiers; hence, a sacred ceremony used to impress an obligation; a solemn oath-taking; an oath
2. (noun)Sacrament the pledge or token of an oath or solemn covenant; a sacred thing; a mystery
3. (noun)Sacrament one of the solemn religious ordinances enjoined by Christ, the head of the Christian church, to be observed by his followers; hence, specifically, the eucharist; the Lord's Supper