The terms "MAC" and "PC" originated from historical distinctions between two different types of personal computers: Macintosh (MAC) computers and IBM-compatible Personal Computers (PCs).
In the 1980s, Apple introduced their line of personal computers called Macintosh or Mac for short. These computers had a unique operating system and hardware architecture developed by Apple. The term "MAC" was used to differentiate Apple's Macintosh computers from other personal computers available in the market.
On the other hand, the term "PC" was initially used to refer to IBM-compatible personal computers. IBM introduced their first personal computer in 1981, and it became a widely adopted standard. Other manufacturers began producing computers compatible with IBM's architecture and operating system, and these machines came to be known as IBM-compatible PCs or simply PCs.
Over time, the term "PC" started to be used more broadly to refer to any personal computer running a Microsoft Windows operating system or any computer that follows the IBM-compatible architecture, regardless of the manufacturer. This usage extended beyond just IBM-compatible machines.
So, to summarize, "MAC" originally referred to Apple's line of Macintosh computers, while "PC" initially distinguished IBM-compatible personal computers from Apple's Macintosh computers. However, the term "PC" later became more inclusive and is commonly used to describe any personal computer, regardless of the manufacturer or operating system.