Definition of: prolusion

(prō·l′zhən) noun
1. That which is introductory to the principal effort or performance; a preliminary attempt; a prolog; prelude.
2. An essay written as a test of the writer's powers, or as preliminary to a more elaborate treatise. [<L prolusio, -onis prelude <prolusus, pp. of proludere play beforehand <pro- before + ludere play]