di-vido

[Lavrentivs]

does dividere mean to "vide" in two, such that we (should) have trividere &c?

[Sceptra Tenens]

No, di- simply gives the notion of separation, as in diripio, differo, dilacero, dilabor, which are "I loot, I scatter, I tear to shreds, I fall apart" respectively. It is clearly shown that this word has no notion of two in Caesar's De Bello Gallico 1.1.1: Gallia est omnis divisa in partes tres, "Gaul is as a whole divided into three parts."

[adrianus]

Cur non et anglicè et latinè trividere pro dividere in partes tres? Quod superfluum est id dictum? Divisio est separatio quod per separationem duarum partium continuò explicatur. Eâ ratione, e viduare non videre verbo modo incerto conceptum esse postulo.

Why not also trivide in English? It's superfluous, no doubt. Division is a separation that happens typically of one piece from another (therein a sense of two), and one cut after another. I could see the word more as deriving in some way from viduare before videre.

Salve, Sceptra Tenens. Jam inceperam cum epistulam tuam animadverti, exinde "duarum partium sensus" inter ancones addidi.