Well in 1993 I think it was
Real
American
Wrestling
They had the red, white and blue ropes if I remember correctly from the network I was barely a year old when Raw came out and didn't even like wrestling until 2004. I know around the New Generation and Attitude Era it became more of sexual innuendo with Sunny saying I like it Raw (yuck) and over time just basically more a way of saying it's real, live and you get it as it comes. I will say even though the PG era was actually pretty good near the beginning. Raw stopped being Raw when they changed the ropes and used a more flashy set around 2006-2010