Antibodies (also known as immunoglobulins[1]) are proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses. They are made of a few...

Atlanta Braves, a MLB Baseball team

Ab is a Dutch name.

Abbot, in the Christian Church; when the term Ab. follows the name of a Christian saint it denotes that the saint was an Abbot.

Assembly Bill

Airman Basic, the lowest rank in the United States Air Force.

One of the human blood types in the ABO blood group system

Adult Baby, one who engages in infantilism.

Anheuser-Busch, the world's third largest brewing company

Abscesses caused by injections, especially heroin injection

Air Berlin, IATA code

Aryan Brotherhood, an American gang

Acton-Boxborough Regional High School, commonly abbreviated as AB

Able Seaman (occupation), a civilian occupation

Andris Biedriņš, basketball player

Abkhazian language (ISO 639 language code)

Bachelor of Arts

Akademisk Boldklub, a Danish professional football club

A^B class, a locomotive class operated by the New Zealand Railways Department

Semitic for "father", see Ab (father)

AB-Aktion, short for Außerordentliche Befriedungsaktion, the German extermination of Polish intelligentsia in World War II

Able Seaman (rank), a naval rank

Category of abelian groups

Alfa-Vita Vassilopoulos, a Greek supermarket chain

At Bat, baseball statistic

Address book

Av (month), a month in the Hebrew calendar

Aktiebolag, Swedish for "corporation", similar to AG, Ltd or Inc

Indo-European for "water", see ap (water).

Allen-Bradley, manufacturer of industrial control and automation products

AB Airlines, a defunct British airline

"Able-Bodied", as used by some members of the disabled community

Aitareya Brahmana

Abdominal muscles (abbreviated Ab), which are the rectus abdominis or the stomach muscles

ab The ApacheBench command line tool for Apache HTTP Server

Canada's subdomain for Alberta

Aberdeen, after which the UK postal area AB is named.

Albania (WMO country code)

Alberta (Canadian Province/Territory Code)

Ancienne Belgique, Belgian concert hall located in Brussels

Alderson-Broaddus College, a liberal-arts college in West Virginia

Good Eats host Alton Brown's nickname

Afrikaner Broederbond, the South African secret society from 1918-1994

Aharonov-Bohm effect arising in a certain experiment of quantum mechanics.

AB is the nickname of legendary Australian cricketer Allan Border