The term - front "bar"

[Dragger_Dan]

In race terms they seem to call it a splitter, which makes sense if actually used for that purpose.

An example of this would be in NZ V8's where the front "splitter" is used to split the gap between the 2 cars that haven't quite got the same corner exit speed as you, or are braking 10 meters before what you thought the correct braking point and using the front "spliiter" to push the cars wide enough apart for you to get through.
Adj splitting to cut things cleanly in half of more than one things into there respective pieces

LOL

[Hybridd]

We call them bumpers here in South Africa_and front or rear "spoilers" if they are aftermarket parts etc.I think the Aussie's refer to them as "bar".