The Parts of a Church
Medieval architects designed most Romanesque and Gothic churches starting with the design of a Roman basilica. But many churches added a part coming out crossways, so that the whole church was built in the shape of a cross, to give more room for people to see the mass, and to remind people how Jesus died on the cross. This sideways part was the transept.
The east part of the church, where the altar was and the choir sang, was called the choir. The rounded end of the choir was called the apse (pronounced APPS). The west end of the church, where people stood to watch the priest say Mass, was called the nave, and the side parts off the nave were called the aisles. In the Middle Ages, churches usually didn't have chairs in them, and people stood up, or they brought their own folding chairs.