No, ROM chips are manufactured with the data an intrinsic part of the silicon, the chip mask changes for different data. If it's writable once, it's a PROM, not a ROM.
And if it's erasable by UV light it's an EPROM
And if instead of UV light you can use a higher voltage to erase it, it's electrically erasable programmable ROM, or EEPROM.
Which these days is pretty much the same as the generic "flash memory" term that you've used.
So.... where were we again?
Oh yeah, ROM being a poorly chosen misnomer. I disagree.
"ROM" - to the end user, past and present - is software you can't change. The BASIC interpreter on your C64, the section of Android that boots and runs the basic system apps, that package is referred to as a ROM, be it a physical chip with a UV window, or these days the zip file that is sent around and then programmed into your EEPROM on your phone.
If someone gave me an OS/9 ROM for my COCO II, yes, that would be a chip. Someone gives me "Bert's Buttery Smooth Vanilla Marshmallow ROM" for my Nexus, well that's a file that gets loaded to my phone, but essentially it's the same item - the operating system.