I made a mistake the other night in stating that PAL is 525 lines of resolution. That’s just PAL M. Currently, NTSC is 525/60hz and PAL is 625/50hz and these are the broadcast resolutions for each. 720×480(NTSC) and 720×576(PAL) are DVD resolutions. So technically I was correct about HD being higher than 525, I just picked the wrong standard. There is no such thing as sub-HD. If you were to use the term sub-HD you would be talking about resolutions lower than HD which are SD and ED. If there is a name for the resolutions between 525 and 720, it hasn’t been documented anywhere.
Thank you and good night!