What does that mean?

Altar	This is always located at the front, it looks like a decorated table and can be made of stone or wood. The offering of the bread and wine is made on the altar by the priest during the Mass which makes a key feature of any Catholic Church.
Blessed Sacrament	The name used to describe the bread and wine after they been blessed and become the body and blood of Jesus.
Catacomb	Caves and tunnels dug outside Rome where the early Christians buried their dead and met to worship God and pray together.
Chapels	Many churches have side chapels, like little churches within the main church. Side chapels are used for small services, often for weekday Mass or Exposition
Congregation	The people who gather to pray together. Another Latin word which means to gather together.
Eucharist	The celebration of the community in which the bread and wine are changed into the body and blood of Christ.
Exposition	A time of prayer in front of the Blessed Sacrament.
Font	The Font is essential in any church, it is the place where through baptism people become Christians and members of the Church. In most churches today you will find it in a very prominent place, usually near the Sanctuary, but in ancient buildings it used to be placed in a special Baptistery (A room or building set apart of baptism). Sometimes it is portable and is moved onto the sanctuary for baptisms
Holy Water	Holy Water is one of the signs of new life, there can be no life without water. Holy water stoups are usually near the doors of the church and many people bless themselves with it as they come and go through the door.
Lectern	Lectern is a odd sort of word, coming from the Latin for reading. The Lectern is the reading desk in the church, the place from which the Bible and prayers are read. Proclaiming God's word is an key part of all church celebrations and so the lectern is normally decorated with a cross or some other symbols to remind us of the reverence to be given to the scriptures. Some churches have stone pulpits which serve the same purpose, to make is easy for the reader to stand and see what they are reading and high enough to be clearly heard by the congregation.
Our Lady	A title used for Mary, the Mother of Jesus.
Paschal Candle	A new Paschal Candle is blessed each year during the Easter vigil. It is the Easter candle and a symbol of the new, risen life of Christ which we all share in.
Sanctuary	If the church were a theatre then the sanctuary would be the stage. This is the area at the front of the church where everything happens - the altar is the central focus of attention but there are several other items which are usually found on the sanctuary. Often the tabernacle is placed close to the altar, but behind it, but it can be placed in a separate chapel or to one one side.
Sanctuary Light	This light, either a candle or an oil lamp, is lit as a sign that Christ is present in the tabernacle. It reminds catholics of the real presence, of the Blessed Sacrament, which is present in the church.
Scripture	A word sometimes used for the Bible, it means the writings.
Stations of the Cross	The Stations of the Cross are one of the aids to prayer in a church, they show the journey of Jesus on his way to his crucifixion. There are 14 Stations which are usually placed around the walls of the church so that people praying the stations can walk around and make a journey as did Jesus on his way to Calvary.
Tabernacle	The tabernacle is basically a cupboard, a place where the Blessed Sacrament is kept securely stored for when Holy Communion is to be taken to the sick and for prayer. It is given special reverence because it contains the Eucharist, the Body of Christ.
Vestments	The special clothes worn by the priest and those with roles in worship.
Votive Lights	Lighting votive candles has been a long tradition among Christians. It is not the offering or some kind of sacrifice but the flame is a symbol for our prayers rising to God. They tend to found near the statues in a church, especially in front of the statues of the Sacred Heart and of Mary.