Fifth grade is the year in which students begin to grow up. They no longer get recess in the morning and they have to actually pass their classes. They also get Mrs. Granger, the only language arts teacher at Lincoln Elementary. She's an older lady who has a perfect attendance record, white hair, and exactly two skirt suits. Despite being short, she seems like a giant: she has dark gray eyes that she can "turn on" and make students feel small. Supposedly she also can tell good jokes, but she's not famous for those.
The description of Mrs. Granger suggests that she's in a class by herself as a teacher and possibly cannot be manipulated like Mrs. Avery and Miss Deaver were. This indicates that teachers have their own hierarchy within the public school system, and teachers like Mrs. Granger have far more power than Mrs. Avery and Miss Deaver.
The students believe that Mrs. Granger has X-ray vision, as she seems to know immediately whenever someone is chewing gum. If she catches a student with gum, she makes them spit it out onto an index card, safety pins the card to the victim's shirt, and makes them bring the card back to school the next day signed by a parent.
Though all of this makes Mrs. Granger terrifying, she's known best for her homework and her love of the dictionary. She's known for assigning weekly vocabulary lists that include 35 words, as well as a "Word for the Day" every morning. Mrs. Granger seems to know when students don't write those down and look up the definitions, as she then assigns the students in question two words of the day. She keeps a full set of dictionaries in her classroom as well as one absurdly heavy dictionary that sits on its own table. All of her former students remember her telling them to look things up.
Mrs. Granger's affinity for the dictionary is understandable given that she teaches language arts, but it's also worth keeping in mind that having a firm grasp of a language allows someone to more fully and more easily participate in society as an adult. This begins to show that what Mrs. Granger is teaching is actually applicable in the outside world, not just in a classroom setting.
In August, before fifth grade begins, Nick's parents get a letter from Mrs. Granger. It reads that every student is expected to have access to one of her preferred dictionaries at home, so that they can expand their vocabularies and properly complete their homework. Nick's mom, Mrs. Allen, thinks it's great that Mrs. Granger takes her job so seriously, but Nick just groans. He likes words and likes to read, but he prefers to ask Mr. Allen or his brother James for a word's definition if he doesn't know it. He's heard that Mrs. Granger won't stand for this, and with a sense of dread, he remembers seeing fifth graders studying hard with their dictionaries last year.
Nick's preference for asking people he knows when he doesn't know something suggests that he already believes in a more communal approach to language, rather than simply going to the dictionary as the final and official word on the matter. This sets up the conflict between the two with Nick supporting communal action and Mrs. Granger supporting deference to established systems of power.