The game we play and others play is football.
Until someone tried to unify the rules there were many versions, depending usually on the school where the game was played.
Hacking was the big problem, that basically was the reason for the creation of The Football Association (Simplified any arguments another thread), that left the ball handlers and hackers as another group.
Some of the ball handlers then decided that they didn't want hacking and formed the RFU, leaving the hackers in the minority.
Eventually the hackers fell in line with the non-hackers and you had two codes, Association (known quite early as soccer) and Union versions of football,
Football was the origin, played at all schools under different rules, including Rugby.
When the Association was born the differentiation was did you use the rules of Rugby School or the new Association of Football Clubs,
All none Association Clubs by default became Rugby Football Clubs,
The Rugby Football clubs where still playing under local school rules though, until the formation of the RFU, then all hell let loose a few years later.
- l'angelo mysterioso likes this