sacrament (n.) Look up sacrament at Dictionary.com
"outward and visible sign of inward and spiritual grace," also "the eucharist," c.1200, from Old French sacrament "consecration; mystery" (12c., Modern French sacrement) and directly from Latin sacramentum "a consecrating" (also source of Spanish sacramento, German Sakrament, etc.), from sacrare "to consecrate" (see sacred); a Church Latin loan-translation of Greek mysterion (see mystery).

Meaning "a holy mystery" in English is from late 14c. The seven sacraments are baptism, penance, confirmation, holy orders, the Eucharist, matrimony, and anointing of the sick (extreme unction).