Assisting in memory; helping to remember; as, a mnemonic device. [1913 Webster]
, n.
Something used to assist the memory, as an easily remembered acronym or verse. [WordNet 1.5]
An abbreviated word that resembles the full word, used so as to be easily recognized; as, the CIDE uses ... tags as mnemnonics for an italicised word or field. [PJC]