Another option I haven't seen yet is つまり, which is to the effect of "In short...", and is used as a lead-in for a brief summary.
Here are some examples taken from the Tanaka Corpus:
My grandmother is hard of hearing. In other words she is slightly deaf.
He is very fat, that is, he weighs 300 pounds.
It shows that English is no longer the language only of the people of England.
The last example, in particular, I think captures that nuance that you're looking for.