A concept sort is a strategy used to introduce students to the vocabulary of a new topic or book. Teachers provide students with a list of terms or concepts from reading material. Students place words into different categories based on each word's meaning. Categories can be defined by the teacher or by the students. When used before reading, concept sorts provide an opportunity for a teacher to see what his or her students already know about the given content. When used after reading, teachers can assess their students' understanding of the concepts presented.