Question: What does the word “sacrament” mean?
Answer: The word “sacrament” means “a sacred oneness or sacred relationship with God.”
Partaking of the sacrament, as a renewal of the baptism covenant, shows a willingness to come into the fold of God. It also shows a willingness to bear the burdens of others and to stand as a witness of God “at all times and in all things” (Mosiah 18:8-9).
In the sacrament prayer over the bread, those who partake of the bread, are admonished to take upon themselves Christ’s name and always remember Him and keep His commandments. When these commitments are met, the Lord promises “that they may always have His Spirit to be with them” (Moroni 4:3; D&C 20:77).
In the sacrament prayer over the water, partakers are asked to remember the Atonement of Jesus Christ and to always remember Him. When these commitments are met, the Lord promises that “they may have His spirit to be with them” (Moroni 5:2; D&C 20:79).
Source: 400 Questions and Answers About the Book of Mormon by Susan Easton Black, p. 211.