9. Naming Magic
According to the Starfleet Medical Reference Manual, TRIcorders are "in practise a small sensor/computer/recorder" or a "TRI-function reCORDER". The fact that the meaning of the name has never been discussed explicitly on screen gets the Star Trek: Lower Decks treatment in the soon to be released U.S.S. Cerritos Crew Handbook, as Ensign Rutherford states, "Good old Trikey! They call it a tricorder but it 'cords so many more than three things!" In Star Trek: Enterprise, they were just called 'hand scanners,' of course. Simpler times!
What it does 'cord,' as a matter of advanced future science fact, does just as well to be mostly indistinguishable from magic, a handy device to move the plot along — we're never actually shown the tricorder operations manual! Occasionally, TV magic also clashes with in-world practicalities. Just how did Voyager get those tricorder 'upgrades' in season two? If you believe Rick Sternbach, they had them in the cargo bay all along.
The TOS-era tricorders weren't given a model number until perhaps most recently in Those Old Scientists when Boimler suggested that "TS-122" might be the model's true name, with the "TS-120" being a predecessor. Trek's following century then gave us a whole new series of names for a brand new series of tricorders.