| area of potential pollution | område med forureningsrisiko |
| Area of the world | Verdensdel |
| area under stress | belastningsfelt |
| Arecaceae | Palme-familien |
| Arecales | Palme-ordenen |
| Arecibo Observatory | Arecibo Observatoriet |
| arena | arena |
| Arenal Volcano | Volcán Arenal |
| Arendal | Arendal |
| Areogel | Kolloid |
| Areole | Areola |
| Ares | Ares |
| Ares I | Ares I |
| Arete | Bjergkam |
| Aretha Franklin | Aretha Franklin |
| Arg-é Bam | Bam |
| argent | sølv |
| Argenteuil | Argenteuil |
| Argentina | Argentina |
| Argentina anserina | Gåse-Potentil |
| Argentine | Argentina |
| Argentine Air Force | Fuerza Aérea Argentina |
| Argentine Republic | Argentina |
| Argentine Tango | Tango |
| Argentine woman | Argentina |
| Argentum | Sølv |
| Arges | Argeş |
| Argeş | Argeş |
| Argeş County | Argeş |
| Argeş River | Argeş |
| Arghakhanchi District | Arghakhanchi District |
| Argiope bruennichi | Hvepseedderkop |
| Argo | Argo Navis |
| Argo Navis | Argo Navis |
| argon | argon |
| Argonaut | Argonaut |
| Argos | Argos |
| Argos System | Argos |
| argument | skænderi |
| Argument of periapsis | Periapsisargument |
| Argument of the perihelion | Periapsisargument |
| Argus | Argos |
| Argus Panoptes | Argus |
| Aria | Arie |
| Ariadne | Ariadne |
| Ariadne auf Naxos | Ariadne på Naxos |
| Arian | Arier |
| Ariana | Ariadne |
| Ariane | Ariane |
| Arianism | Arianisme |
| Ariansim | Arianisme |
| arid land | aridt område |
| Aride | Utaknemlig |
| Ariel Ltd | Ariel |
| Ariel Ramírez | Ariel Ramírez |
| Ariel Sharon | Ariel Sharon |
| Aries | Vædderen |
| Aries Mu | My |
| Ariete | Vædderen |
| Arild | Arild |
| Arild Huitfeldt | Arild Huitfeldt |
| Arion | Skovsnegl |
| Arion fuscus | Brunsnegl |
| Arion rufus | Rød skovsnegl |
| Ariosophy | Ariosofi |
| Ariplane | Luftfartøj |
| arise | være født |
| Aristarchus | Aristarchos |
| Aristarchus of Samos | Aristarchos |
| Aristarchus of Samothrace | Aristarchos |
| aristocracy | aristokrati |
| Aristolochia | Slangerod-slægten |
| Aristolochia clematitis | Hjertebladet Slangerod |
| Aristolochiaceae | Slangerod-familien |
| Aristophanes | Aristofanes |
| Aristoteles | Aristoteles |
| Aristotelian ethics | Moral |
| Aristotle | Aristoteles |
| arithmetic | aritmetik |
