A bit more on why the question and how you've come upon the term.
The simplest answer, and not probably what helps you, is that SSL Termination is: "the termination of an SSL session"
Where you "could" have encountered the term is someone decided to write something or use that term to indicate their definition of one endpoint of an SSL connection. And that is also a simple sounding answer, which is that any SSL connection has two endpoints, one side started the connection and the other side accepted the connection. One could "claim" that each side of the connection is an "SSL Termination" and that would be simple verbiage use on the part of whoever invented it.
Therefore, understanding how you encountered the term and why you're asking the question helps a bit here.