No need to apologize all they are is model designations anymore.
Originally after WWII when Jeeps were being produced for civilians it was given the designation as a CJ (CJ 2, CJ 3, etc) meaning Civilian Jeep. That designation ran from WWII till 1987 when the Jeep Wrangler came out as the YJ which ran from 1987-1995. Then the newer models came as the TJ which was from 1996-2006. Now the newest models (which includes yours) are the JK 2007- current.
There is many variations such as the new four door models are JKU which is JK unlimited or the TJ models that were "unlimited" are called LJs. All jeep vehicles have these designations like certain year cherokees are xk's. There is FSJ, KJ, and many many more do some digging online and learn some about the history more including the jeep wave. I find it to be quite interesting! And....... welcome!!!