that it depended on who the cop worked for would determine what they are called. City cop - Officer; County cop - Deputy; State cop - Trooper (in Utah).

But there are also various ranks within each department: officer, corporal, sergeant, lieutenant, captain, chief, etc.

So my question is: Is it bad form to call a lieutenant a "deputy" (for a county cop) or "officer" (for a city cop)? Or do people need to learn what the stripes mean on their uniforms in order to use the correct title?