What is the difference between nonmonogomy and polyamory?

I’m trying to navigate realizing I’m somewhere on this spectrum, and I’m even curious potentially playing with a couple. Before I start any of this I’m not looking to engage in harmful stereotypes by entering a dynamic and not being educated to an extent. Everytime I ask this question, I’m lead to nonmonogomy yet I’m confused by the difference? Also is the term,”unicorn” okay to use? I most identify with this label but it appears this is a harmful word (based on people saying in comments) but no other term is used in replace of this? If there is a word what should I be using instead?