Iris Thaumantia

IRIS (Iris), a daughter of Thaumas (whence she is called Thaumantias, Virg. Aen. ix. 5) and Electra, and sister of the Harpies. (Hes. Theog. 266, 780; Apollod. i. 2. § 6; Plat. Theaet. p. 155. d; Plut. de Plac. Philos. iii. 5.) In the Homeric poems she appears as the minister of the Olympian gods, who carries messages from Ida to Olympus, from gods to gods, and from gods to men. (Il. xv. 144, xxiv. 78, 95, ii. 787, xviii. 168, Hymn. in Apoll. Del. 102, &c.) In accordance with these functions of Iris, her name is commonly derived from erô eirô; so that Iris would mean "the speaker or messenger:" but it is not impossible that it may be connected with eirô, "I join," whence eirênê ; so that Iris, the goddess of the rainbow, would be the joiner or conciliator, or the messenger of heaven, who restores peace in nature.

Source: Dictionary of Greek and Roman Biography and Mythology.

Nonnus, Dionysiaca 47. 340 ff :
"Iris the bride of Zephyros and mother of Pothos (Desire)."