Some are organizational and acknowledged as being Scientology; e.g. the Sea Org, OSA (Office of Special Affairs, formerly GO, Guardian's Office), Bridge Publications.
Some are what the buildings are generally or specifically called; e.g., Orgs (general), Missions (tiny "org" usually located in a private home, from what I've gathered), St. Hill, Ideal Orgs (expensive buildings purchased to give the Religious Technology Center / COB (Chairman of the Board) more real estate holdings and the True Believers something to waste money on, and to convince them Scientology is "expanding"), Gold, Big Blue, Int Base, Celebrity Centres (Orgs hoping to rook in the future rich and powerful and famous idiots out there with too much expendable income).
Some are front groups that pretend to not be affiliated with Scientology in order to indoctrinate the unwary; e.g. WISE, ABLE, Narconon
That feeling you get--the confusion at all the alphabet soup and weird abuses of the English language--is a calculated effect designed to make the "in crowd" feel special and important and to get them all talking in a special language that prohibits independent thought and expression and to alienate / confuse the non-cultists, who are not supposed to understand all the jargon and code spewed at them.