epiphonema
[ep-uh-foh-nee-muh]
noun
1.
a sentence that is an exclamation, a general or striking comment, or a succinct summary of what has previously been said.
Source
dictionary.com
Examples
To round off his argument, Montaigne reaches for an epiphonema ... "Oh, what a sweet and soft and healthy pillow is ignorance and incuriosity, to rest a well-made head!"
-- Kathy Eden, "Cicero's Port