Ballista and Bowie knife

Ballista noun - An engine that provided medieval artillery used during sieges; a heavy war engine for hurling large stones and other missiles.

Bowie knife and ballista are semantically related. in arm topic. In some cases you can use "Bowie knife" instead a noun "Ballista".

Bowie knife noun - A stout hunting knife with a single edge.

Ballista and bowie knife are semantically related. You can use "Ballista" instead a noun phrase "Bowie knife".