Internal-combustion engine and Outboard

Internal-combustion engine noun - A heat engine in which combustion occurs inside the engine rather than in a separate furnace; heat expands a gas that either moves a piston or turns a gas turbine.

Outboard and internal-combustion engine are semantically related. In some cases you can replace term "Outboard" with "Internal-combustion engine", this terms are similar.

Outboard noun - Internal-combustion engine that mounts at stern of small boat.

Internal-combustion engine and outboard are semantically related. Sometimes you can use "Internal-combustion engine" instead a noun "Outboard".