I’m going to flip out if I hear someone say “Pin number” again. How do people not realize that the “n” in “pin” already stands for “number”?
Here’s what PIN stands for:
Personal Identification Number
So when you say “Oh, here’s my Pin number”, you are actually saying, “Oh, here’s my Personal Identification Number Number”. Sounds dumb, doesn’t it? That’s because it is dumb. Just say “PIN”, and leave it at that.
Note that this applies to SIN (social insurance number), VIN (vehicle identification number), TIN (taxable identification number), DIN (drug identification number), and a host of others. Notice the pattern?