I know this is an unecessarily long comment for what might just be a typo, but I'd like to know If I'm getting this right myself. I believe 'a pleb' is short f

I know this is an unecessarily long comment for what might just be a typo, but I'd like to know If I'm getting this right myself. I believe 'a pleb' is short for 'a plebeian'. 'Plebs' would be plural of 'pleb', so 'a plebs' seems incorrect. I could be wrong though. English is not my first language, and I'd love to be corrected if I indeed am wrong.