IPA: /prəˈluːʃəri/
KK: /prəˈluːʃəri/
Relating to something that serves as a preliminary or introductory part, often leading to a main event or idea.
The prolusory remarks set the stage for the main presentation.
Prolusory is formed from "pro-" (meaning before) and "lusor" (from Latin, meaning player or one who plays). The word refers to something that serves as a preliminary or introductory play or exercise.
Think of 'before' ('pro-') and 'player' ('lusor') to remember that 'prolusory' means something that is an introductory play or exercise.