296. The altar, on which is effected the Sacrifice of the Cross made present under sacramental signs, is also the table of the Lord to which the People of God is convoked to participate in the Mass, and it is also the center of the thanksgiving that is accomplished through the Eucharist.
Word hounds take note: an altar is also a table. More words, more ways of describing enrich such an important aspect of liturgy.
297. The celebration of the Eucharist in a sacred place is to take place on an altar; however, outside a sacred place, it may take place on a suitable table, always with the use of a cloth, a corporal, a cross, and candles.
298. It is desirable that in every church there be a fixed altar, since this more clearly and permanently signifies Christ Jesus, the Living Stone (1 Pt 2:4; cf. Eph 2:20). In other places set aside for sacred celebrations, the altar may be movable.
An altar is said to be fixed if it is so constructed as to be attached to the floor and not removable; it is said to be movable if it can be displaced.
My parish has a movable altar. It takes four determined people to budge it, however. It would be interesting to know the thinking behind that decision. What about your parish?