"aiding the memory," 1753, back-formation from mnemonics, or from Greek mnemonikos "of or pertaining to memory," from mnemon (genitive mnemonos) "remembering, mindful," from memne "memory, a remembrance, record, an epitaph; memory as a mental faculty," from base of mnasthai "remember," from PIE root *men- "to think" (see mind (n.)). The noun meaning "mnemonic device" is from 1858. Related: Mnemonical (1660s).
mnemonic mne·mon·ic (nĭ-mŏn'ĭk)
Relating to, assisting, or intended to assist the memory. n.
A device, such as a formula or rhyme, used as an aid in remembering.
A word or string which is intended to be easier to remember than the thing it stands for. Most often used in "instruction mnemonic" which are so called because they are easier to remember than the binary patterns they stand for. Non-printing ASCII characters also have mnemonics like NAK, ESC, DEL intended to evoke their meaning on certain systems.