Okay people, we have to call it something? My thinking (I apologize for all the acronyms): The Dilithium Crystals (DC) generate ship power from the M/AM reaction (don't know how, but they are work together to provide main/warp power). When the DC are associated with the M/AM reaction, they "convert" the M/AM energy into power for the ship probably by charging up or "energizing" the ship's EPS. The M/AM reaction takes place in the M/AM reaction chamber. (TWS) There is an intermix temperature and intermix formula (probably for the M/AM reaction itself). (TCM, TNT) "Doodad" on the engine room floor added. Season 2 had a box with dark blue heat exchanger fins on top. https://i.ibb.co/1vrpByD/doomsdaymachine-ER.jpg (Enterprise's box is on the console side. Maybe the DC are inside of it but need more work to remove them or removed from below.) Note that one of the bronze balls is blown, so, too much power/heat was inside of it. Or it got fried from an external electrical/plasma arc from the vertical power shaft (shown on right of it) when it blew first, or visa versa. Scott moved this line out of the Enterprise's engine room in Season 1 because it was too vulnerable to external damage (TEW). No dilithium mentioned, yet. In Season 3, the Dilithium Crystals (DC) are installed in which looks like an "articulation frame", located in the box between the two triangular sub-doodads (EOT). Converter Assembly (MW) and the Dilithium Crystal Converter Assembly, DCCA, (EOT) are terms mentioned. Is the DC "articulation frame" the DCCA itself, or does it just hold the DC and transports them into and out of the DCCA (which holds up to 4 crystals) thats connected inside the M/AM reaction chamber? I prefer something like the later. Doodad double cylinder shape may suggest: some sort of safety system node into the reaction chamber to insert and extract the DC articulation frame in and out of the DCCA while in the active M/AM reaction. Purpose: the design suggests either a dual field containment system to breach the active reaction, and/or they may may be dual energizing coils to on-line re-amplify the DC to replace the off-line dilithium crystal energizer (DCE) seen in TAF https://memory-alpha.fandom.com/wiki/Energizer. Since Mres likes the new term "synchrotron", which sounds cool , it could be the dilithium crystal synchrotron (DCS) or dilithium synchrotron (DS) or just synchrotron for short. hate to add another option but, the doodad could be the main energizer itself where the super-charged DC are inserted to extract the stored energy and send it into the ship EPS via the pipe cathedral. Season 3 put an access hatch on the box that can remove the DC from the floor mounted doodad that also removes it from the DCCA which is in the active M/AM reaction chamber. The Star Trek web site (http://www.startrek.com/database_article/dilithium-chamber-hatch) gives: Dilithium Chamber Hatch (DCH), "Exterior door of the matter/antimatter reaction chamber, part of the warp drive of a starship. The hatch gives crewmen access to the dilithium crystal articulation frame when the frame requires service or the crystals need replacing." A good name for the hatch if it was directly attached to the M/AM reaction chamber: Now, is the floor doodad the actual Matter/Antimatter Reaction Chamber? One cylinder is matter and the other antimatter with the dilithium crystal directly between them. Wow. Probably not; too TNG: I know we don't like to use TNG terms, but Memory Alpha gives: "The dilithium crystal chamber (or dilithium regulation chamber or matter-antimatter chamber or dilithium chamber) was a component in a starship's warp core that contained the dilithium crystals. No, this sounds like the entire M/AM reaction chamber and "chamber" sounds bigger than that doodad on the floor. How to explain a common doodad if there are multiple engine rooms, especially if one is in the saucer? My conclusion: It's most likely the dilithium crystal energizer (DCE) (with the access hatch added in Season 3) that energizes the DC when they need re-amplifying, and it conveniently transports the DC in its articulation frame in and out of the DCCA. Systems upgraded are the dilithium energizing and direct access to the dilithium articulation frame on the engineering floor, both systems previously done below decks and now consolidated in main engineering. Any saucer engine room(s) would not have this feature, rather it will look like the Season 1 engine room. Any secondary hull engine room(s) would have this feature. Later in TMP, it was moved into a side room, and even later in TMG, it was not needed anymore since they did it in place. What to call it? I plan to use the term dilithium crystal energizer (DCE) in my posts for now unless TrekBBS come up with better answer...YMMV.