system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did Jack become a nickname for John?
gpt
>The name Jack dates back to about 1,200 and was originally used as a generic name for peasants. Over time, Jack worked his way into words such as lumberjack and steeplejack. Even jackass, the commonly used term for a donkey, retains its generic essence in the word Jack. Of course, John was once used as a generic name for English commoners and peasants, (John Doe) which could be why Jack came became his nickname. But the more likely explanation is that Normans added -kin when they wanted to make a diminutive. And Jen was their way of saying John. So little John became Jenkin and time turned that into Jakin, which ultimately became Jack.