The term was first coined in the 1930s by Swiss astronomer Fritz Zwicky, who observed unexpected movements in the Coma Cluster of galaxies. He realized that the galaxies were moving faster than could be explained by the visible matter alone. This led him to postulate the existence of an unseen "dark matter" that contributed to the cluster's gravity.
So, the name is more of a description of its properties, rather than a reference to something specific. It's basically saying "we know something is there, but we can't see it, and it's acting like matter."