Which is borrowed from Greek too, indeed:
pō̆lўpŭs,
i, [or
odis] m. (
fem., Lucil. ap. Non. 220, 4), =
πολύπους (first in Arist.), later Gr. for πουλύπους, ποδος, ὁ ; [...] — the common
poulp or
octopus,
Od. l.c., Thgn.
l.c., Arist.
HA 524a3, etc. of insects, Id.
PA 682a36, al. ; esp. of the myriapods, Id.
HA 531b29, al.
I. An aquatic animal,
sea-polypus: Sepia octopodia, Linn.: piscis polypus, Plaut. Rud. 4, 3, 71; Plin. 9, 12, 14, § 40; 9, 19, 35, § 71 al. (Jahn, polybi); Lucil. l. l.; Enn. ap. App. Mag. p. 299 (Heduph. v. 10 Vahl.); Ov. M. 4, 366; id. Hal. 31 (with the o long).—Transf., of rapacious men, Plaut. Aul. 2, 2, 21...
Octopus is however attested in later Latin. My dictionary quotes Alexander of Tralles (5. 16) and the Medical Pliny (2. 22).
en.wikipedia.org
en.wikipedia.org