For the lazy, here [1,2] are some wiktionary links. Assuming these are correct, wow, this makes the whole main vs master thing seem even more silly.
> SLAVE: From Middle English, from Old French sclave, from Medieval Latin sclāvus (“slave”), from Late Latin Sclāvus (“Slav”), because Slavs were often forced into slavery in the Middle Ages.[1][2][3][4][5] The Latin word is from Byzantine Greek Σκλάβος (Sklábos), see that entry and Slav for more.
> ROBOT: Borrowed from Czech robot, from robota (“drudgery, servitude”). Coined in the 1921 science-fiction play R.U.R. (Rossum's Universal Robots) by Karel Čapek after having been suggested to him by his brother Josef, and taken into English without change.
Well that ruins the fun of the surprise a little... but I guess people can still look forward to real plot twist: who the "masters" were. Hint: it wasn't the Moops!
> SLAVE: From Middle English, from Old French sclave, from Medieval Latin sclāvus (“slave”), from Late Latin Sclāvus (“Slav”), because Slavs were often forced into slavery in the Middle Ages.[1][2][3][4][5] The Latin word is from Byzantine Greek Σκλάβος (Sklábos), see that entry and Slav for more.
> ROBOT: Borrowed from Czech robot, from robota (“drudgery, servitude”). Coined in the 1921 science-fiction play R.U.R. (Rossum's Universal Robots) by Karel Čapek after having been suggested to him by his brother Josef, and taken into English without change.
[1]: https://en.wiktionary.org/wiki/slave#Etymology [2]: https://en.wiktionary.org/wiki/robot#Etymology