Tunnelsystem (German) comes from German Tunnel, from English Tunnel, from Old French tonel, from Old French tone, from Late Latin tunna, from Proto-Celtic tunna — hide, skin.
Tunnelsystem (German): tunnel system a network of connected tunnels
Definitions
tunnel system a network of connected tunnels
Ancestry of “Tunnelsystem”, step by step
Tunnelsystem traces back through two separate lines of ancestry.