The term "dn" can refer to various concepts depending on the context. In mathematics, "dn" often represents a differential notation, indicating a small change in a variable. It is commonly used in calculus to denote infinitesimal changes in functions or equations. In the realm of technology, "dn" can also stand for "domain name," which is a human-readable address used to access websites on the internet. A domain name is part of the Domain Name System (DNS), which translates user-friendly names into numerical IP addresses that computers use to identify each other on the network.