Wiktionary
n. (context astronomy English) an area of intense tectonic activity on the surface of Mars; photographed in detail by Mars Express
Wikipedia
Acheron Fossae is a trough in the Diacria quadrangle of Mars. Its location is centered at 37.67° north latitude and 135.87° west longitude. It is 718 km long and is named after a classical albedo feature at 35°N, 140°W . The trough has seen intensive tectonic activity in the past.
Acheron Fossae - topography map.png|Topography map of Acheron Fossae Acheron Fossae Crater.JPG|Acheron Fossae Dissected Crater, as seen by HiRISE. Part of eroded floor is shown in image. Acheron Fossae.JPG|Acheron Fossae, as seen by HiRISE. Scale bar is 1000 meters long. Click on image to see dark slope streaks. Slope Streaks in Acheron Fossae on Mars.jpg|One theory is dark sand flowed down the slopes of Acheron Fossae. However, they lighten in color over time. ESP 045804 2200channel.jpg|Channel in Acheron Fossae, as seen by HiRISE under HiWish program ESP 045896 2190channels.jpg|Channels, as seen by HiRISE under HiWish program
Usage examples of "acheron fossae".
Vlad and Ursula had relocated their biotech complex to a finlike ridge in the Acheron Fossae.