I have been wondering for a while already about the usage of "specimen size"
to describe an orchid plant.

I remember a photo in an old AOS bulletin of a just awarded Miltonia hybrid
that had over 500 flowers and I think was in a 24 inch pot. It weighed over 100
pounds. I'd call that a specimen.

I think there are specific rules for awarding well grown plants. It used to be
a CCM or Certificate of Cultural Merit. I don't know the specifics but I'm sure
someone who is either a judge or student judge could provide the information.