Triaxilation was a type of modulation that could be applied in various technologies.
By the mid-22nd century, triaxilating a comm signal had become a method used by Starfleet to make a signal secure. Communications Officer Hoshi Sato noted that a triaxilated signal would remain completely undetected even if one was sent from inside Starfleet Headquarters. (ENT: "Detained") In 2151, the Coridanite rebel Traeg used a triaxilating signal to communicate his demands of weapons to the Enterprise. The audio signal was received by the ship, but its origin could not be traced due to the triaxilation. (ENT: "Shadows of P'Jem") Even by 2375, the origin of a communication signal on triaxilating wavelengths could not be determined. (VOY: "Nothing Human")
When Arturis planted a false message to the badly damaged Starfleet data stream in 2374, he claimed to have extracted the iconometric elements of the stream and then to have triaxilated a recursion matrix from them. (VOY: "Hope and Fear")
Drones in Unimatrix Zero were linked together with an interlink frequency on a triaxilating modulation. It could not be disrupted by the Borg Queen. Seven of Nine was later unable to isolate the frequency and deflector pulses were used to disrupt it. (VOY: "Unimatrix Zero", "Unimatrix Zero, Part II")
The Borg triaxilated deflector shield geometry to absorb the energy of phaser pulses modulated to change frequencies. (VOY: "Dark Frontier") The Borg, however, could not instantaneously adapt and usually took a few shots through their shields first. However, when a Borg cube knew beforehand the frequencies of even a massive energy burst, such as one emitted by the USS Enterprise-D in 2366, they could absorb it completely without taking any damage. (TNG: "The Best of Both Worlds", et al.)
Antiphoton pulses could be used to disrupt the signals of heavily armored holo-emitters. The pulse was emitted on a triaxilating frequency, and would shut down any emitter without damaging the program it was projecting. Emitters could still be protected from the pulse using deflector shields, or by emitting a feedback surge on the inverse triaxilating frequency to counter the pulse. (VOY: "Flesh and Blood")