Category: Lists of two-letter combinations .ad is the Internet country code top-level domain (ccTLD) for Andorra. ... Assistant director is a movie term for an assistant to the director whose duties include tracking the progress of filming versus the production schedule, and preparing call sheets. ... Wikipedia does not yet have an article with this exact name. ... Algemeen Dagblad is a Dutch newspaper. ... Ad (Arabic عاد) was an ancient Arabian nation mentioned in the Quran as being the place where the Islamic prophet Hud (هود) was sent to by Allah to guide its people back to the righteous path of Islam. ... Anno Domini Nostri Iesu Christi (In the Year of Our Lord Jesus Christ), commonly shortened to Anno Domini (In the Year of the Lord), abbreviated as AD or A.D., is the designation used to number years in the Christian Era, conventionally used with the Julian and Gregorian calendars. ... Generally speaking, advertising is the promotion of goods, services, companies and ideas, usually by an identified sponsor. ... American troops man an anti-aircraft gun near the Algerian coastline in 1943 Anti-aircraft warfare, or air defense, is any method of engaging military aircraft in combat from the ground. ... The Air Department of the British Admiralty was established prior to World War I by Winston Churchill. ... In mathematics and computer algebra, automatic differentiation, or AD, sometimes alternatively called algorithmic differentiation, is a method to numerically evaluate the derivative of a function specified by a computer program. ... In mathematics, the axiom of determinacy (abbreviated as AD) is an axiom in set theory. ... Autodynamics is a replacement for special relativity and general relativity proposed by physicist Ricardo Carezani, in the early 1940s. ... Audio description refers to an additional narration track for blind and visually impaired viewers of visual media, including television and movies, dance, opera, and visual art. ... Administrative domain is when all the networks and network devices under the control of one particular organization. ... Active Directory (codename Cascade) is an implementation of LDAP directory services by Microsoft for use in Windows environments. ... Air Paradise is an airline based in Indonesia. ... In economics, aggregate demand is the total demand for goods and services in the economy (Y) during a specific time period. ... In electronics, an analog-to-digital converter (abbreviated ADC, A/D, or A to D) is a device that converts continuous signals to discrete digital numbers. ... It has been suggested that Acronym and initialism be merged into this article or section. ... The English language contains various two-letter words. ...