| arbitrage | arbitrage |
| arbiträr | arbitrary |
| Arboga kommun | Arboga Municipality |
| Arbois | Arbois |
| arboretum | arboretum |
| Arbroath | Arbroath |
| Arbroath Abbey | Arbroath Abbey |
| Arca Caesarea | Arqa |
| Arcade Fire | Arcade Fire |
| Arcadius | Arcadius |
| Arcangelo Corelli | Arcangelo Corelli |
| Arcelor Mittal | Arcelor Mittal |
| Arcelor-Mittal | Mittal Steel Company |
| Arch Linux | Arch Linux |
| Archaeoceratops oshimai | Archaeoceratops |
| Archaeodontosaurus descouensi | Archaeodontosaurus |
| Archaeopteryx | Archaeopteryx |
| Archaeornithoides deinosauriscus | Archaeornithoides |
| Archaeornithomimus | Archaeornithomimus |
| Archangaj | Arkhangai Province |
| Archangelsk | Arkhangelsk |
| Archangelsk oblast | Arkhangelsk Oblast |
| Arche | Arche |
| Archelaos | Herod Archelaus |
| Archer Martin | Archer John Porter Martin |
| Archibald Sayce | Archibald Sayce |
| Archidamos II | Archidamus II |
| Archilochos | Archilochus |
| Archipielago de los Chonos | Chonos Archipelago |
| Archlord | ArchLord |
| Archytas | Archytas |
| Arconciel | Arconciel |
| Arcot | Arcot |
| Arctodus simus | Arctodus |
| Arcturus | Arcturus |
| Arcus tangens | Inverse trigonometric function |
| Arda | Arda |
| Ardabil | Ardabil Province |
| Ardahan | Ardahan Province |
| Ardalan Shekarabi | Ardalan |
| Ardashir I Papagan | Ardashir I |
| Arden | Arden |
| Ardenner | Ardennes |
| ardennerhäst | Ardennes carthorse |
| Ardennerna | Ardennes |
| Ardenneroffensiven | Battle of the Bulge |
| Ardennes | Ardennes |
| Ardens kommun | Arden municipality |
| Ardez | Ardez |
| Ardipithecus | Ardipithecus |
| Ards | Ards Borough Council |
| Ardulfurataini Watan | Ardulfurataini Watan |
| Ardèche | Ardèche |
| area | area |
| areal | acreage |
| areal i acres | acreage |
| Arecibo-observatoriet | Arecibo Observatory |
| arena | arena |
| Arenarock | Arena rock |
| Arenberg | Arenberg |
| Arendal kommun | Arendal |
| Areografi | Geography of Mars |
| Areol | Areole |
| Areopagen | Areopagus |
| Arequipa | Arequipa |
| Ares | Ares |
| Ares I | Ares I |
| Ares V | Ares V |
| Arete | Arete |
| Aretha Franklin | Aretha Franklin |
| Arethusa | Arethusa |
| Areva | Areva |
| Arex | Arex |
| Arezzo | Arezzo |
| arg | mad |
| Arg-é Bam | Arg-é Bam |
| Arga unga män | Angry young men |
| argbigga | scold |
| Argentanspets | Argentan lace |
| Argenteuil | Argenteuil |
| Argentina | Argentina |
| argentinare | Argentinian |
