Knowing what one is reading is of the utmost importance. When reading any text, one must make sure that he or she looks up any words which are not known or understood. If one skips over the term, he or she may lose the meaning of the sentence or passage.
Paul Zindel's The Pigman, although written for young adults, does include some terminology which may need defining or explaining. Here are a few words/phrases which may not be known to some readers.
"Sound mind and body" ( from "The Oath") refers to one being healthy and in his or her right mind.
"Porcelain unmentionables" (2) refers to a toilet.
"Avocation" (2) refers to a hobby.
"Incandescent" (3) refers to something which emits (gives off) light.
"Commemorative" (3) refers to something which honors something.