mnestic adj.

1753, "aiding the memory, intended to assist the memory;" 1825, "pertaining to the memory," a back-formation from mnemonics, or from a Latinized form of Greek mnēmonikos "of or pertaining to memory," from mnēmōn (genitive mnēmonos) "remembering, mindful," from mnēmē "memory, a remembrance, record, an epitaph; memory as a mental faculty," from base of mnasthai "remember," from PIE root *men- (1) "to think." The noun meaning "mnemonic device" is from 1858. Related: Mnemonical (1660s).

Middle English -ik, -ick, word-forming element making adjectives, "having to do with, having the nature of, being, made of, caused by, similar to," from French -ique and directly from Latin -icus or from cognate Greek -ikos "in the manner of; pertaining to." From PIE adjective suffix *-(i)ko, which also yielded Slavic -isku, adjectival suffix indicating origin, the source of the -sky (Russian -skii) in many surnames. In chemistry, indicating a higher valence than names in -ous (first in benzoic, 1791).

In Middle English and after often spelled -ick, -ike, -ique. Variant forms in -ick (critick, ethick) were common in early Modern English and survived in English dictionaries into early 19c. This spelling was supported by Johnson but opposed by Webster, who prevailed.