Flumen orationis is from Cicero's Brutus (274), where it describes the style of the orator Caelius as having an abundant and flowing river of speech. Students should note that the river metaphor for discourse implies several things simultaneously: abundance (the river is full),
continuity (it flows without breaks), power (it can carry things along), and directionality (it flows toward a destination).
These qualities are all rhetorical ideals — the speech or poem that is full, continuous, powerful, and purposeful. The phrase should be contrasted with the style described as laconic (from the Spartans, who were famous for brief, pithy speech) and with the compressed, elliptical styles of Tacitus,
Hopkins, and Celan. Related terms include the genera dicendi (the three styles of speaking: high, middle, and plain), abundantia (verbal copiousness), and Cicero's concept of the perfect orator
as one who can command all three styles.