The story
- Proto-Indo-European*weǵʰ-
- Proto-Indo-European*wéǵʰeti
- Proto-Italic*weɣō
- Latinvehō
- Latinvector
- English todayvector
Learned borrowing from Latin vector (“carrier, transporter”), from vehō (“to carry, transport, bear”), also ultimately the root of English vehicle. The “person or entity that passes along an urban legend or other meme” sense derives from the disease sense. The mathematics sense was coined by Irish mathematician and astronomer William Rowan Hamilton in 1846.
Etymology from Wiktionary, CC BY-SA 4.0.