"Rom" / "rom byte" keywords?

[Robotics Guy]

I'm trying to program a microcontroller in C to communicate with my laptop over a USB connection. The code examples that I've been able to find have the descriptors written either like this:

ROM USB_DEVICE_DESCRIPTOR device_dsc=
{
    0x12,    // Size of this descriptor in bytes
    USB_DESCRIPTOR_DEVICE,                // DEVICE descriptor type
    0x0200,                 // USB Spec Release Number in BCD format
    0x00,                   // Class Code
    0x00,                   // Subclass code
    0x00,                   // Protocol code
    USB_EP0_BUFF_SIZE,          // Max packet size for EP0, see usb_config.h
    0x04D8,                 // Vendor ID
    0x003F,                 // Product ID: Mouse in a circle fw demo
    0x0002,                 // Device release number in BCD format
    0x01,                   // Manufacturer string index
    0x02,                   // Product string index
    0x00,                   // Device serial number string index
    0x01                    // Number of possible configurations
};

Or this:

	rom byte deviceDescriptor[] =
	{
		0x12, 0x01, // bLength, bDescriptorType
		0x00, 0x02, // bcdUSB (low byte), bcdUSB (high byte)
		0x00, 0x00, // bDeviceClass, bDeviceSubClass
		0x00, E0SZ, // bDeviceProtocl, bMaxPacketSize
		0xD8, 0x04, // idVendor (low byte), idVendor (high byte)
		0xFF, 0x01, // idProduct (low byte), idProduct (high byte)
		0x01, 0x00, // bcdDevice (low byte), bcdDevice (high byte)
		0x01, 0x02, // iManufacturer, iProduct
		0x00, 0x01  // iSerialNumber (none), bNumConfigurations
	};

The problem is, I have no idea what the "rom" and "rom byte" words mean. I've looked through my C programming book and have searched Google but have come up with nothing. Can anyone point me in the right direction?

Thanks