Pancake engine and Rotary engine

Rotary engine and pancake engine are semantically related In some cases you can replace phrase "Rotary engine" with "Pancake engine", this phrases are similar.

Rotary engine noun - An internal-combustion engine in which power is transmitted directly to rotating components.

Pancake engine and rotary engine are semantically related in internal-combustion engine topic. You can use "Pancake engine" instead a noun phrase "Rotary engine".