No, write protecting a floppy disk makes it a Read Only floppy disk (perhaps Read Only Data?). The 'M' for memory usually refers to that used in silicon chips accessed by the CPU not software.
The Amiga is not limited to use only a Kickstart ROM, but software (especially games which is what people usually request when they ask for ROMS) usually comes in the form of disk images/files.
In the course of marketing referring to things such as compact discs as "CD-ROM"s also adds to the confusion. I remember when any PC with a CD drive attached was referred to as a "Multimedia" PC. And what ever happened to the Information Superhighway? Did Microsoft ever finish building that?