Latin aquaeductus combines aquae, of water, and ductus, an act of leading. The name describes the work of the channel.
Sources
- Merriam-Webster: aqueduct
Word History and Kids Etymology give the components and grammatical meanings; Did you know connects ducere and explains that many aqueducts were underground.
- Online Etymology Dictionary: duct
Also from Latin *ductus* "a leading": duct
- Online Etymology Dictionary · aqueduct
Meanings of the older forms on the word path.