The story
From eco- (prefix meaning ‘ecology; the environment’) + (via)duct (“bridge with several spans that carries traffic over a valley or other obstacles”).
First known use, by meaning
- from late 20th c. A type of wildlife crossing in the form of a bridge or tunnel, usually covered with foliage and turf, which animals may use to cross roads without the risk of being hit by vehicles; a wildlife viaduct.
Etymology from Wiktionary, CC BY-SA 4.0.