As RAM is the Main Memory then is ROM a secondary memory???

RAM stands for Random Access Memory. That distinguishes it from drum, disk, or shift register memories, which allow access only when your data location comes around. Rom stands for Read Only Memory, which means it is written or stamped or otherwise recorded and you can't change it. Some ROM is programmable integrated circuits, some is electrically eraseable, EEROM, some is electrically rewriteable, EWROM, some is compact disk, CD, some is digital video disc, DVD. Your computer contains its startup (boot) program in an integrated circuit ROM. A CD is often called a ROM disk. Endless variety. In the early days up to the 1970s, punched cards were the only memory.