.ad is the Internet country code top-level domain (ccTLD) for Andorra. It is administered by Servei de Telecomunicacions d'Andorra, today called Andorra Telecom.

An ad (advertisement) is a form of marketing communication.

In set theory, AD+ is an extension, proposed by W. Hugh Woodin, to the axiom of determinacy. The axiom, which is to be understood in the context of ZF plus DC_R (the axiom of dependent choice for real numbers), states two things:

1. Every set of reals is ∞-Borel.
2. For any ordinal λ less than Θ, any subset A of ω^ω, and any continuous function π:λ^ω→ω^ω, the preimage π⁻¹[A] is determined. (Here λ^ω is to be given the product topology, starting with the discrete topology on λ.)

Advaita, (stylised as AD\/\ITA) is the annual technical and cultural festival of International Institute of Information Technology, Bhubaneswar, held during the month of February within the university campus. It is a grand four day festival event, the maiden edition of which was held in 2013. It attracted thousand of students from all over India, including students, academia, corporates and the general public of the state. The fourth edition of Advaita is going to be held from 11 February to 14 February in the year 2016.

Advertising (or advertizing) is a form of marketing communication used to promote or sell something, usually a business's product or service.

Alpha Delta (ΑΔ) may refer to:

• Alpha Delta (Dartmouth), a derecognized Greek organization at Dartmouth College
• Alpha Delta National Fraternity, founded in 2007

American Dad! is an American adult animated sitcom created by Seth MacFarlane, Mike Barker, and Matt Weitzman for the Fox Broadcasting Company. American Dad! is the first television series to have its inception on Animation Domination. The series premiere aired on February 6, 2005, following Super Bowl XXXIX, three months before the rest of the first season aired as part of the Animation Domination block, commencing on May 1, 2005.

The term anno Domini is Medieval Latin, which means in the year of the Lord but is often translated as in the year of our Lord. It is occasionally set out more fully as anno Domini nostri Iesu (or Jesu) Christi ("in the year of Our Lord Jesus Christ"). The terms (AD or A.D.) and before Christ (BC or B.C.) are used to label or number years in the Julian and Gregorian calendars.

Audio description, also referred to as a video description or more precisely called a visual description, is an additional narration track intended primarily for blind and visually impaired consumers of visual media (including television and film, dance, opera, and visual art). It consists of a narrator talking through the presentation, describing what is happening on the screen or stage during the natural pauses in the audio, and sometimes during dialogue if deemed necessary.