I have no idea... normally when hybrids are designated they use F1 and F2 for various stages of hybridization. It sounds like someone that is just trying to show a difference between two plants that may or may not really be different. I would ask them directly what they mean by that designation and if it actually refers to the number of hybridizations that have been staged between several species or merely a made up designation for plants that simply look different despite similar parentage.

What it sounds like is that in the resultant offspring of the hybridization there were distinctly recognizable variants, probably in the leaf morphology, such as size or height or the color. In orchids hybrids are identified by varietal names such as "Pink Boy" with the name in quotations marks.

My guess is it could be hybrid or non hybrid or maybe color variation.