Definition of "proem"

Thus much may serve by way of proem; / Proceed we therefore to our poem.

1731, Jonathan Swift, On the Death of Dr. Swift

The natural coherence and connection of the proem with the account of our Saviour's ministry, lead us to adopt this explication, which is pertinent and consistent.

1836, William Johns, An Essay on the Interpretation of the Proem to John's Gospel, with an Appendix, page 10

On our first reading, we obviously cannot know of the role that Aristaeus will play at the end of the work, but when we do encounter him there, we should remember his appearance in the proem: a clear link between the georgic and the pastoral […]

2010, Christopher Nappa, Reading After Actium: Vergil's Georgics, Octavian, and Rome, University of Michigan Press, page 28