D defs.my
Entry 1 sense Webster, 1913

Prolusion

· Pro·lu·sion · IPA
01 n. A trial before the principal performance; a prelude; hence, an introductory essay or exercise.
  1. 1.
    A trial before the principal performance; a prelude; hence, an introductory essay or exercise.
    “Her presence was in some measure a restraint on the worthy divine, whose prolusion lasted.” Sir W. Scott.