Regina earned her degree in entymology after successfully defending her thesis, titled "Guesstimation at the expresso stand: the impact of misnomers in coffee culture".
You learnone new fact (e.g. the scientific name of an insect...) and an old fact pops out of your head.
The "entymologist's dilemma" occurred to me when I tried to recall the term for the roll-around cart that you use to work under a car...(a "creeper" by the way). (don't ask me what the term was that dropped out of my head...!)