Edumaction, I Gotted Some

So, this guy decided to read the OED and write a book about it. And then write some blog posts, including one about absurd entries. Oddly enough, I mostly understand the definition for trondhjemite* - 'Any leucocratic tonalite, esp. one in which the plagioclase is oligoclase’. As you can guess from the "ite" ending, it is a geologic term (a rock).
( Cut for explanation of defination )