> personal pin number

It's your personal personal identification number number

The PIN you use to prove it's your card, when you use it in an ATM or in a chip and PIN reader.

I'm going to hazard a guess that @ggambetta is making a veiled reference to "RAS Syndrome".

https://en.wikipedia.org/wiki/RAS_syndrome

Off topic, but is there a name for names that are diagnostic or demonstrative of the thing. Eg you can't say 'lisp' with a lisp, have trouble spelling dyslexia with dyslexia. 'hippopotomonstrosesquippedaliophobia' is the fear of long words, TLA (three letter acronym) and the above obviously.

I think you are looking for: https://en.wikipedia.org/wiki/Autological_word

Perhaps? The examples given seem much more limited to the qualities of the word itself, I'm not sure the lisp example would fit under that banner.

That page does link to 'Ostensive definition' though:

"An ostensive definition conveys the meaning of a term by pointing out examples"

So perhaps 'Auto-ostensive'?

https://en.m.wikipedia.org/wiki/Ostensive_definition

Yep :) Didn't know it was called that.

It's refreshing to see the correct capitalisation and no redundant words in your sentence :)

It's the one you use in the ATM Machine :)

I only use automatic ATM machines.

It's your personal identification pin number