The Gray Lady?

[jspotila at yahoo.com]

No: HPFGUIDX 30180

I've checked the lexicon and FAQ but can't find any references to 
where the books name her "The Gray Lady."  I know in SS ch. 12 she is 
the unnamed ghost witch passing Harry and Ron on their way to the 
mirror.  But where oh where in the books is she referred to as the 
Gray Lady?

Thank you thank you.

Jennie