Raven's Progressive Matrices (RPM)
Here's your citation in American Psychological Association (APA) format:
Raven's Progressive Matrices (RPM). (n.d.). In Alleydog.com's online glossary. Retrieved from: https://www.alleydog.com/glossary/definition-cit.php?term=Raven%27s+Progressive+Matrices+%28RPM%29