A brief explanation of some liturgical terms:

Call to Worship: A passage of scripture that is read to prepare worshippers to enter into God's presence.
Silent Prayer: To ready and focus worshippers on their meeting with God.
Votum: Is a Latin term meaning vow or prayer. It is a confession and response to God's command to worship. Here the worshippers declare their total dependence on God.
Salutation: God's greeting to his people.
Benediction: God's blessing to his people.
Word: Reading and Preaching from the Bible, God's word to humanity.
Sacrament: Baptism and Holy Communion (Lord's Supper) Physical signs that display spiritual truths
Baptism and Holy Communion (Lord's Supper)

For more information about Reformed Worship (offsite):

What is Reformed Worship?
Worship Evangelical or Reformed?
URC learning on Liturgy (MP3 audio resource)
The Beauty of Reformed Worship