Wisdom teeth: the large molars located at the very back of the jaw. The human jaw has changed in size over the course of evolution, and wisdom teeth are no longer needed, but they continue to erupt in many individuals. If the jaw is too small to accommodate them, they may cause pain or crowd other teeth out of position. An impacted wisdom tooth refers to a wisdom tooth that has not erupted due to blockage from other teeth. Wisdom teeth may need to be removed surgically.