What is the role of parity in quantum mechanics?

[Chronos000]

I'm unsure about how parity is used or indeed what it actually is in quantum mechanics. If someone could shed some light on this it'd be a great help.

 

[Rick88]

parity is something very simple.

If you have an object (or curve, equation..) in x, y, z, let x-> -x, y-> -y, z-> -z.
If the body (or equation or curve) looks exactly the same as before, then parity is conserved.
Otherwise, it is violated.R.