Congo snake and Salamander

Congo snake noun - Aquatic eel-shaped salamander having two pairs of very small feet; of still muddy waters in the southern United States.

Salamander and congo snake are semantically related. In some cases you can use "Salamander" instead a noun phrase "Congo snake".

Salamander noun - Any of various typically terrestrial amphibians that resemble lizards and that return to water only to breed.

Congo snake and salamander are semantically related. Sometimes you can replace phrase "Congo snake" with "Salamander", this terms are similar.