From the start of the book:
"Each time you see a word that is highlighted, [...] it means that this term is a lexicon enabled term. By clicking on that term, you will see a page listing all other uses of that term within the book."
"Each time you see a word that is highlighted, [...] it means that this term is a lexicon enabled term. By clicking on that term, you will see a page listing all other uses of that term within the book."