The word slave arrived in English via the Old French sclave. In Medieval Latin the word was sclavus and in Byzantine Greek σκλάβος.[11] Use of the word arose during the Early Medieval Period, when Slavs from Central and Eastern Europe (Saqaliba) were frequently enslaved by Moors from the Iberian Peninsula and North Africa
The Romans had slaves aka slavs.
https://en.wikipedia.org/wiki/Slavery#:~:text=The%20word%20slave%20arrived%20in,Iberian%20Peninsula%20and%20North%20Africa.
people were enslaving eachother for a long time.