"I find this immensely interesting, and have done some deep digging and made a video about the topic:
The earliest source I found is from a 1980 arcade operating manual of Space Panic, mentioning bosses. Another enemy in that game is a 'don'.
In early 1980's Japan, "bosu" (loanword from English) had a derogatory connotation to do with Mafia. Translating "bosu" would give you "boss", but in English the negative meaning is not present.
Old Kung Fu films use this term for mobsters too (Bruce Lee in The Big Boss).
RsNoobLord on November 16th, 2017 at 13:44 UTC »
Actually it has a weird etymology outside of western influence (kind of?), having to deal with organized crime:
https://youtu.be/v8X-NCH8HfI?t=1m41s
from the maker of the video:
found here: https://gaming.stackexchange.com/questions/33359/why-are-bosses-called-bosses
GottIstTot on November 16th, 2017 at 14:09 UTC »
To be fair, it's the boss of the dungeon, not the boss of the player.
Louie-Lecon-Don on November 16th, 2017 at 15:16 UTC »
From now on, you can call me. Big Boss.