Final answer:
A Uniform Resource Locator (URL) primarily identifies Web content, linking text to the IP address and location on the host where the content can be found.
Step-by-step explanation:
A Uniform Resource Locator (URL) primarily identifies Web content. A URL is used to specify the exact location of a webpage on the internet by mapping letters and words to an IP address and location on the host server. When citing sources online, a URL is crucial and should be as specific as possible to allow readers to find the original source easily. Meanwhile, a DOI, or digital object identifier, is another system used to locate online resources and is particularly useful for academic journals because it remains constant even if the URL changes. It's important to note that the domain name within a URL can indicate the nature of a website, such as .edu for educational institutions, .gov for government sites, and .org for nonprofit organizations.