Arachosia
αὐτὸν κέκρουκας τὸν βατῆρα τοῦ λόγου → you have struck the very threshold of the argument, you have struck the most important and chiefmost point
Latin > English (Lewis & Short)
Ărăchōsĭa: ae, f., = Ἀραχωσία.
I A province of the Persian kingdom, separated from India by the Indus, Plin. 6, 23, 25, § 82.—Hence,
II Derivv.
A Ără-chōsĭi, ōrum, m., the inhabitants of Arachosia, Just. 13, 4.—
B Ărăchōtae, ārum, m., the same, Prisc. Perieg. 1003.
Latin > French (Gaffiot 2016)
Ărăchōsĭa, æ, f., province perse : Plin. 6, 92 || -chōsĭī, ōrum, m., Curt. 4, 5, 5, ou -chōtī, ōrum, Just. 13, 4, 22, ou -chōtæ, ārum, m. Plin. 6, 92, Arachosiens.
Wikipedia EN
Arachosia (/ærəˈkoʊsiə/; Greek: Ἀραχωσία Arachōsíā), or Harauvatis (Old Persian: 𐏃𐎼𐎢𐎺𐎫𐎡𐏁 Harauvatiš), was a satrapy of the Achaemenid Empire. Primarily centred around the Arghandab River, a tributary of the Helmand River, it extended as far east as the Indus River. The satrapy's Persian-language name is the etymological equivalent of Sárasvatī in Vedic Sanskrit. In Greek, the satrapy's name was derived from Arachōtós, the Greek-language name for the Arghandab River. Around 330 BCE, Alexander the Great commissioned the building of Alexandropolis as Arachosia's new capital city under the Macedonian Empire. It was built on top of an earlier Persian military fortress after Alexander's conquest of Persia, and is the site of today's Kandahar in Afghanistan.
"Arachosia" is the Latinized form of Greek Ἀραχωσία (Arachōsíā). "The same region appears in the Avestan Vidēvdāt (1.12) under the indigenous dialect form 𐬵𐬀𐬭𐬀𐬓𐬀𐬌𐬙𐬍 Haraxvaitī- (whose -axva- is typical non-Avestan)." In Old Persian inscriptions, the region is referred to as 𐏃𐎼𐎢𐎺𐎫𐎡𐏁, written h(a)-r(a)-u-v(a)-t-i. This form is the "etymological equivalent" of Vedic Sanskrit Sarasvatī-, the name of a river literally meaning "rich in waters/lakes" and derived from sáras- "lake, pond." (cf. Aredvi Sura Anahita).
"Arachosia" was named after the name of a river that runs through it, known in ancient Greek as the Arachōtós and today as the Arghandab River, a left-bank tributary of the Helmand River.