score:4
He means the same thing as "the old covenant" (Judaism), but stated in the language of dispensationalism, which classifies the different timeline "slices" of God's plan. We tend to think of it as old covenant/new covenant but if you start getting really anal about it and analyzing "what about before Moses" and "what about after the Rapture" you get a bit more of a complicated set of salvation schemes over time, or "dispensations."
Edit: I guess I'm surprised that this is a contentious or misunderstood point, has no one heard of dispensationalism? I provided the links above for a reason. Mastery and escape: T.S. Eliot and the dialectic of modernism discusses Eliot's dispensationalism specifically and how he uses this term in much of his writing. He was, you know, into it.