Final answer:
The nave elevation in Western medieval churches is a vertical cross-section showing the interior structure, such as the arcade, triforium, and clerestory, which are designed to create an uplifting sense and illuminate the nave.
Step-by-step explanation:
The nave elevation of a Western medieval church refers to the vertical cross-section of the interior of a nave, which is the central and primary part of a Christian church. This elevation typically consisted of several levels, each with a different architectural purpose and aesthetic. The lowest level is usually the arcade, comprising a row of arches standing on columns that separate the nave from the aisles. Above the arcade might be the triforium, a shallow, decorative gallery sometimes present in Romanesque or Gothic churches. At the highest level is the clerestory, which is a high section of wall that contains windows to admit light into the nave. In many Gothic cathedrals, the nave elevation is notable for its impressive verticality and the sense of uplift it imparts to the structure, with each level drawing the eye upward towards the heavens.