| Aristotle | Archaeology | Arithmetic mean |
| Architecture (disambiguation) | Arithmetic and logical unit | Arraignment |
| ArgumentArgument may refer to: (in logic) a logical argument that is, an attempt to proved a demonstration of the truth of a conclusion based on the truth of a set of premises (in mathematics) at least three different things: a parameter or independent variable t | Argument formIn logic, the argument form or test form of an argument results from replacing the different words, or sentences, that make up the argument with letters, along the lines of algebra; the letters represent logical variables''. The sentence forms which class | ArubaAruba is an island in the Caribbean Sea, just a short distance north of the Venezuelan Paraguana Peninsula, and it forms a part of the Kingdom of the Netherlands. It is very dry, with little of the tropical vegetation that many expect in the Caribbean. |
| Articles of ConfederationThe Articles of Confederation was the first governing document of the United States of America. The Articles combined the colonies of the American Revolutionary War into a loose confederation. The second Continental Congress adopted the Articles of Confed | Arthur KoestlerArthur Koestler ( September 5, 1905 1983) was a novelist, political activist, and social philosopher. He was the author of many popular books including Arrow in the Blue (Volume I of his autobiography), The Yogi and the Commissar (another book about Commu | Arthur SchopenhauerArthur Schopenhauer ( February 22, 1788 September 21, 1860) is one of the most important 19th century philosophers, most famous for his work, The World as Will and Representation''. He is known for having espoused a sort of philosophical pessimism that sa |
| Arctic OceanThe Arctic Ocean located entirely in the north polar region, is the smallest of the world's five oceans (after the Pacific Ocean, Atlantic Ocean, Indian Ocean, and Southern Ocean), and the shallowest. It occupies a roughly circular basin and covers an are | Arctic CircleThe Arctic Circle is one of the five major circles of latitude that mark maps of the Earth. This is the parallel of latitude that runs 66° 33' 38" north of the Equator. Everything north of this circle is known as the Arctic, and the zone just to the south | ArgentinaArgentina is a Spanish-speaking country in southern South America, situated between the Andes in the west and the southern Atlantic Ocean in the east. It is bordered by Paraguay and Bolivia in the north, Brazil and Uruguay in the northeast and Chile in th |
| Armenia | Art | Aries |
| Arabic language | Arthur C. Clarke | Argon |
| Arsenic | Arable land | Arne Kaijser |
| Archipelago | Arthur Conan Doyle | Archie |
| Aramaic alphabet | Arguments for the existence of God | Arches National Park |
| Arecales | Aristophanes | Ardipithecus |
| ARY Digital | Artificial intelligence | Architect |
| Articles of Faith | Artistic revolution | Area |
| Artist | Archaea | Arthur Meighen |
| Arianism | Argot | Arminianism |
| Aromatic hydrocarbon | Arabian Prince | Army |
| Arachnophobia | Arthur Aikin | Arnold Matthew |
| Arthritis | Arabic numerals | Arnold Schwarzenegger |
| Archimedes | Archimedean solid | Aromatic compound |
| Arizona State University | Art Deco | Argo Navis |
| Ara | Arkansas | Arizona |
| Architectural engineering | Argument from common consent | Argument from morality |
| Archery | Arbor Day | Ares |
| Array | Aristide Maillol | Ark |
| Arizona Cardinals | Arene | Arizona Diamondbacks |
| Ark of the Covenant | Armour | Armoured fighting vehicle |
| Artistic License | Arsenal F.C. | Arcadius |
| Arab | Armadillo | Arabs and anti-Semitism |
| Arcology | Arabic alphabet | Arctic fox |
| Armenian language | Ariel | Arthur Stanley Eddington |
| Armoured personnel carrier | Armored car | Aramaic language |
| Arthur Miller | Area 51 | Archbishop of Canterbury |
| Ardal O'Hanlon | Arrangement | Arthropod |
| Art conservation and restoration | Arc de Triomphe | Artillery |
| Arnulf of Carinthia | Articolo 31 | Aromatherapy |
| ARY Group | Arapawa Island | Arthur Phillip |
| Arbroath Abbey | Arbitration | Archbishop George Abbot |
| Arthur St. Clair | Arthur William a Beckett | Arthur J. Stone |
| Arabian Sea | Aria Giovanni | Arabic |
| Aron Nimzowitsch | Aragonese language | Armenian alphabet |