AD
AD may refer to any of the following:
1. With solicitation or marketing, ad is short for advertisement, a technique used to get consumers to buy a product or service. See our advertisement page for further information and other examples.
2. With computer networking, AD is short for Active Directory. See our Active Directory page for further information about this service.
3. With a signal, A-D is short for analog-to-digital and describes converting an analog signal to a digital one. See our ADC (Analog-to-Digital Converter) page for further information.
4. AD is short for access denied, an error message displayed when a user tries to enter an area on a computer or network without proper permissions. See our access page for further information.
5. When describing a period of time, A.D. is the Latin phrase "anno domini," which means "in the year of the Lord." See our computer history B.C. - A.D. 1000 to see early events in human history that helped develop computers.