A Hybrid CD contains files for the PC based on the ISO 9660 standard and for Apple Macintosh computers based on the HFS standard. Nero creates so-called 'non shared' Hybrid CDs. This means that if you wish to use files on the Mac and on a PC then they must be on the CD twice: Once in the ISO sector and once in the HFS sector.
Caution: If you want to make a Hybrid CD from a PC, the HFS input data must be on an SCSI harddisk connected to the PC. Remember however that the data on the SCSI harddisk can only be created with an Apple Mac computer.