The term luncheon meat comes from a foreign country.
Because everyone was so busy in the 1980s in Hong Kong, many people took lunch meat as their lunch to save time.
In the past, when foreigners worked, they didn't go to tea houses or tea restaurants for fast food like Hong Kong people, but stayed at the company for lunch.
However, because the company can't cook food and the lunch time is not long, the general staff will make their own sandwiches for lunch. At that time, many employees loved to put pieces of meat in sandwiches, and they generally didn't eat these sandwiches for breakfast or dinner. Over time, the pieces of meat sandwiched between sandwiches were called "lunch meat".
See Baidu Encyclopedia.