Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with narwhals, chevrotains, musk deer, water deer, muntjac, pigs, peccaries, hippopotamuses and walruses, or, in the case of elephants, elongated incisors. Tusks share common features such as extra-oral position, growth pattern, composition and structure, and lack of contribution to ingestion. Tusks are thought to have adapted to the extra-oral environments, like dry or aquatic or arctic. In most tusked species both the males and the females have tusks although the males' are larger. Most mammals with tusks have a pair of them growing out from either side of the mouth. Tusks are generally curved and have a smooth, continuous surface. The male narwhal's straight single helical tusk, which usually grows out from the left of the mouth, is an exception to the typical features of tusks described above. Continuous growth of tusks is enabled by formative tissues in the apical openings of the roots of the teeth.

গজদন্ত বলতে হাতির দাঁত বোঝানো হয়। ওপরের পাটির দুটি দীর্ঘ ছেদন দন্তই হাতির দাঁত নামে পরিচিত। দাঁত দুটি সাদাটে। হাতির মুখের নিচের দিক থেকে তরবারির মতো বেরিয়ে থাকে। আফ্রিকার কোন কোন হাতির দাঁতের দৈর্ঘ্য তিন-সাড়ে তিন মিটার পর্যন্ত হয়ে থাকে।