https://docs.freebsd.org/en/books/handbook/book/#dirstructure --- ... A mount point is a directory where additional file systems can be grafted onto a parent file system (usually the root file system). This is further described in Disk Organization. Standard mount points include /usr/, /var/, /tmp/, /mnt/, and /cdrom/. These directories are usually referenced to entries in /etc/fstab. This file is a table of various file systems and mount points and is read by the system. Most of the file systems in /etc/fstab are mounted automatically at boot time from the script rc(8) unless their entry includes noauto. Details can be found in The fstab File. ... /media/ Contains subdirectories to be used as mount points for removable media such as CDs, USB drives, and floppy disks ...
Might be that at some point 'cdrom' changed to 'media' and the handbook was updated only at one place? Version control log should reveal if that was the case.
By the way, there are 2 other places in the handbook where '/cdrom' is mentioned: - 26.2.3.1. Custom Kernels with FreeBSD 9.X and Later - 32.3.1. Configuring the Server Would make sense to update those too?