My housemates have been having a huge argument over this, what do you define as 'cooking'?

The whole of yesterday evening has been a massive debate about what people define as cooking.

Myself and one other housemate define cooking in the dictionary sense in that it's the process of preparing food by heating it.

While the other three house mates are on the side that preparing food is cooking. They believe that just throwing a frozen pizza in the oven and heating it doesn't count as cooking at all; i personally consider it as a low form of cooking but it's still cooking.