The Collaborative International Dictionary
Mnemonical
Mnemonic \Mne*mon"ic\ (n[-e]*m[o^]n"[i^]k), Mnemonical \Mne*mon"ic*al\ (n[-e]*m[o^]n"[i^]*kal), a. [Gr. mnhmoniko`s, fr. mnh`mwn mindful, remembering, mnh`mh memory, mna^sqai to think on, remember; akin to E. mind.] Assisting in memory; helping to remember; as, a mnemonic device.
Wiktionary
mnemonical
a. Assisting in memory; mnemonic.