A mnemonic is a technique that aids memory via associations and cues. A popular one for remembering the biological taxonomy is Kids Prefer Cheese Over Fried Green Spinach (for Kingdom, Phylum, Class, Order, Family, Genus, Species).
Similarly, understanding the differences between modernization, modernism, and modernity is easier if one can remember related terms:
ism = art (e.g., cubism)
ity = experience (e.g., activity)
Or, in learning names one might associate a characteristic with an aspect of the person and their name. For example, since I'm a sci-fi geek, I'm "Joseph the Jedi." But don't be like Michael Scott from The Office: