Mechanical system and Ventilating system

Mechanical system noun - A system of elements that interact on mechanical principles.

Ventilating system and mechanical system are semantically related. In some cases you can replace phrase "Ventilating system" with "Mechanical system", this phrases are similar.

Ventilating system noun - A mechanical system in a building that provides fresh air.

Mechanical system and ventilating system are semantically related. You can use "Mechanical system" instead a noun phrase "Ventilating system".