An ear is the organ that enables hearing and body balance using the vestibular system. In mammals, the ear is usually described as having three parts: the outer ear, the middle ear and the inner ear. The outer ear consists of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. The ear is a self cleaning organ through its relationship with earwax and the ear canals. The ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localization.

मानव व अन्य स्तनधारी प्राणियों मे कर्ण या कान श्रवण प्रणाली का मुख्य अंग है। कशेरुकी प्राणियों मे मछली से लेकर मनुष्य तक कान जीववैज्ञानिक रूप से समान होता है सिर्फ उसकी संरचना गण और प्रजाति के अनुसार भिन्नता का प्रदर्शन करती है। कान वह अंग है जो ध्वनि का पता लगाता है, यह न केवल ध्वनि के लिए एक ग्राहक के रूप में कार्य करता है, अपितु शरीर के संतुलन और स्थिति के बोध में भी एक प्रमुख भूमिका निभाता है।