Aisle A passageway between the areas of seating or pews, usually going from the back to the front (west to east) of the building. A church or chapel may have side aisles parallel to the main, central one. In the picture above we are looking down the central aisle towards the screen with the chancel lying byond that.
Altar Sometimes called the Communion Table. A table, often with a cross standing on it, on which the bread and wine and placed for the service of Communion (sometimes called Eucharist).
Apse A semi-circular recess built sometimes at the east end of a church in place of a chancel or at the eastern end of the chancel.
Chancel The section of the church where the choir sits. It is often separated from the nave, or main body of the church, by a screen and perhaps by one or two steps. The altar is usually at the eastern end of the chancel.
Choir stalls The benches in the chancel where the choristers are seated. Here, instead of facing east as the pews do in the nave, the choir stalls face north or south so that the choristers look across to each other.
Clerestory An extra row of windows, high up towards the roof, on either side of the central aisle. You will find these only in larger churches. In the picture above you can see the clerestory.
Font The basin used to hold the water for baptism (sometimes called Christening). Sometimes you will find the font at the front of the nave but sometimes it stands at the back or side of the church.
Lectern The reading desk which often holds a very large Bible.
Nave The main body of the church, where the members of the congregation are seated.
Pews The benches where members of the congregation are seated. Some churches have chairs rather than pews. In some very old churches you will find box pews - pews with very high sides, backs and fronts.
Pulpit The preaching platform. This is usually reached by a small flight of steps and is, effectively, an ornamental, lidless, box. It is usually at the front of the nave, just to the right or left of the steps leading to the chancel.
Reredos A screen, or tapestry, which stands, or is hung, behind the altar.
Rood Screen The screen dividing the nave from the chancel, often with a cross (or rood) mounted above it.
Transept The ground plan of many churches forms the shape of a cross. The two 'arms' of the cross are the transepts.