CLERESTORY

Clerestory is  term now restricted to the windows in an aisled nave, or to the range of wall in which the high windows are set but was formerly applied to any window or traceried opening in a church, e.g. in an aisle, tower, cloister, or screen, but . Sometimes these windows are very small, being mere quatrefoils or spherical triangles. However, is larger churches they are important features both of beauty and utility. The clerestory is especially used in churches where the division into nave and side aisles permits the introduction of light into the body of the church from above the aisle roofs.

CARLISLE CATHEDRAL
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Acknowledgement: http://www.newadvent.org/cathen/04049a.htm

BASILICA

A  Basilica is a public building of ancient Rome having a central nave with an apse at one or both ends and two side aisles formed by rows of columns, which was used as a courtroom or assembly hall. It is also a Christian church building of a similar design, having a nave with a semicircular apse, two or four side aisles, a narthex, and a clerestory.

ISTVAN BASILICA
Picture taken from : http://www.bestourism.com/medias/dfp/2757

Acknowledgement: http://www.thefreedictionary.com/basilica