"Liturgy is not an event that depends on good ideas and great songs. no one makes up or invents a liturgy. It is something that grew over millennia of faith." (YOUCAT, par. 167)
For Christians, "liturgy" is a public service, duty or work. So, the liturgy is the official public worship of the Chruch, separate from private devotion. It is the special title for the Eucharist, as well as the administration of the sacraments with the annexed use of the sacramentals.
Liturgy is not just the words that are said; it is much more than that. Through the liturgy we encounter God, and are united with our brothers and sisters across the world as the Universal Church.