Steam engine and Tank locomotive

Steam engine noun - External-combustion engine in which heat is used to raise steam which either turns a turbine or forces a piston to move up and down in a cylinder.

Tank locomotive and steam engine are semantically related. In some cases you can use "Tank locomotive" instead a noun phrase "Steam engine".

Tank locomotive noun - A locomotive that carries its own fuel and water; no tender is needed.

Steam engine and tank locomotive are semantically related. You can use "Steam engine" instead a noun phrase "Tank locomotive".