<P> Each student is allowed to bring a cat, toad, rat or owl . Along with the acceptance letter, first - year students are sent a list of required equipment which includes a wand, subject books, a standard size 2 pewter cauldron, a set of brass scales, a set of glass or crystal phials, a kit of basic potion ingredients (for Potions), and a telescope (for Astronomy). The Hogwarts uniform consists of plain work robes in black, a plain black hat, a pair of protective gloves, and a black winter cloak with silver fastenings . Each uniform must contain the wearer's nametag . First years are not allowed a broomstick of their own, though an exception to this rule is made for Harry in his first year after he demonstrates an excellent ability as a Seeker in Quidditch . </P> <P> The primary mode of transport to Hogwarts is the Hogwarts Express that students take at the start of each school year . Students board the train from the also fictional and hidden Platform 93⁄4 at King's Cross station in London . The train arrives near Hogwarts, some time after nightfall . </P> <P> From there, first - year students are accompanied by the "Keeper of the Keys, Game and Grounds" (which was Hagrid during the first novel) to small boats, which magically sail across the lake and get them near the entrance of Hogwarts . The older students ride up to the castle in carriages pulled by creatures called Thestrals . When the first - year students initially arrive at the castle, they wait in a small chamber off the entrance hall until the older students have taken their seats, and then enter the Great Hall for the Sorting Ceremony to determine their House assignments . As teacher Minerva McGonagall said in Harry Potter and the Philosopher's Stone, "The Sorting is a very important ceremony because, while you are here, your House will be something like your family within Hogwarts . You will have classes with the rest of your House, sleep in your House dormitory, and spend free time in your House common room ." After the Sorting Hat sings a song, each student in turn is seated upon the stool in front of the rest of the student body . The Hat is placed on the student's head, whereupon it examines his or her mind and assigns them to one of the four Houses based on abilities, personality, and preferences . After the Sorting Ceremony, the students and teachers enjoy a feast, prepared by the Hogwarts house - elves . If Dumbledore is feeling cheerful, he will lead the students in singing the school song . </P> <P> Hogwarts is divided into four houses, each bearing the last name of its founder: Godric Gryffindor, Salazar Slytherin, Rowena Ravenclaw and Helga Hufflepuff . Throughout the school year, the houses compete for the House Cup, gaining and losing points based on actions such as performance in class and rule violations . The house with the highest end - of - year total wins and has its colours displayed in the Great Hall for the following school year . Each house also has its own Quidditch team that competes for the Quidditch Cup . These two competitions breed rivalries between the houses . Houses at Hogwarts are living and learning communities for their students . Each house is under the authority of one of the Hogwarts staff members . The Heads of the houses, as they are called, are in charge of giving their students important information, dealing with matters of severe punishment, and responding to emergencies in their houses, among other things . Each year, year level groups of every separate house share the same dormitory and classes . The dormitory and common room of a House are, barring rare exceptions, inaccessible to students belonging to other Houses . </P>

What do the houses in harry potter stand for