KYMOPOLEIA (or Cymopoleia) was a Haliad nymph daughter of the god Poseidon and wife of the hundred-handed, storm-giant Briareos. She was probably a goddess of the violent storm waves generated by her stormy husband and, like her husband, presumably was of gigantic form.

Hesiod, Theogony 817 ff (trans. Evelyn-White) (Greek epic C8th or 7th B.C.) :
"But [the three Hekatonkheires] the glorious allies of loud-crashing Zeus have their dwelling upon Okeanos' foundations, even Kottos (Cottus) and Gyes; but Briareos, being goodly, the deep-roaring Earth-Shaker [Poseidon] made his son-in-law, giving him Kymopoleia (Cymopoleia) his daughter to wed."

Hesiod, Theogony 140 ff :
"[The Nereis] Kymodoke (Cymodoce) who, with Kymatolege (Cymatolege) and Amphitrite, light of foot, on the misty face of the open water easily stills the waves and hushes the winds in their blowing."
[N.B. Kymatolege appears in connection with the Nereides, but was not numbered amongst them. She may be the same as Kymopoleia, the daughter of Amphitrite, who is later mentioned by Hesiod.]

Sources:

• Hesiod, Theogony - Greek Epic C8th-7th B.C.