Also known as memoria technica, mnemonics are mental devices that help us to remember more complex concepts or verbal sequences. The principle of mnemonics is to use familiar ideas to incorporate a series of unfamiliar ideas. Those familiar ideas can take the form of anything from word schemes to acronyms.
In music, in order to remember which notes the lines of the treble clef represent (from bottom to top; EGBDF) some mnemonics would be; Every Good Boy Deserves Fudge; Every Good Burger Deserves Fries, or Elvis’ Guitar Broke Down Friday. For the Circle of Fifths (FCGDFA), another example would be; Freddy Can Get Drunk At Every Bar (which brings a whole new meaning the term Circle of Fifths). In computer language, mnemonic systems are used to encode information. The most helpful mnemonics are ones that grab you emotionally. If you found that the Elvis mnemonic was amusing, it will most likely stay with you, hence, its function as an aid to memory.
The word “mnemonic” was derived from the name Mnemosyne, the goddess of memory in Greek mythology (and not Johnny Mnemonic). As to the mysterious appearance of the silent “M”, the first letter of Mnemosyne, one can only conjecture that perhaps it was felt that a goddess should have a more ineffable and majestic-looking name and therefore, in order not to anger her, more letters with arcane pronunciations were required. Another theory is that Mnemosyne herself thought the whole extra “M” thing was rather stupid and hoped we would all forget about it…