Hackers' hangout that's tough to find via search engines

Wikipedia Word definitions in Wikipedia
A darknet (or dark net ) is an overlay network that can only be accessed with specific software, configurations, or authorization, often using non-standard communications protocols and ports . Two typical darknet types are friend-to-friend networks (usually ...

Wiktionary Word definitions in Wiktionary
n. (context network computing English) a closed private network of computers used for file sharing.