| Acetat de potassi | Acetat de sodi | Acetat de vinil |
| Acetat de zinc | Acetàbul | Acetàbul (morfologia) |
| Acetògens | Acetònid de fluocinolona | Acetil |
| Acetil CoA | Acetil coenzima A | Acetil-CoA |
| Acetil-CoA carboxilasa | Acetilació | Acetilació de proteïnes |
| Acetilè | Acetilcisteïna | Acetilcolina |
| Acetilcolinesterasa | Acetilcolinesterases | Acetiloxi |
| Acetilur | Acetoacetat | Acetoacetat d'etil |
| Acetoïna | Acetobacter | Acetobacteraceae |
| Acetobacteràcia | Acetobacteri | Acetobacteriaceae |
| Acetobacteriàcia | Acetobacteriàcies | Acetobacteris |
| Acetobacterium | Acetobàcter | Acetogènesi |
| Acetogen | Acetona | Acetonitril |
| Acetosa sagittata | Acetoxi | Acetyl CoA |
| Acetyl-CoA | Aceuchal | Aceuchal (Badajoz) |
| Acevedo | ACF | ACF Brescia |
| ACF Fiorentina | ACF Fiorentina Youth Sector | Acfred I d'Aquitània |
| Acfred I d’Aquitània | Acfred I de Carcassona | Acfred II de Carcassona |
| ACG | ACGAF | ACGC |
| Ach gott vom himne sieh dades, BWV 2 | Ach Gott, vom Himmel sieh darein | Ach Gott, vom Himmel sieh darein, BWV 2 |
| Ach Gott, wie manches Herzeleid | Ach Gott, wie manches Herzeleid, BWV 3 | Ach Gott, wie manches Herzeleid, BWV 58 |
| Ach Herr, mich armen Sünder, BWV 135 | Ach wie flüchtig, ach wie nichtig, BWV 26 | Ach! ich sehe, itzt, da ich zur Hochzeit gehe, BWV 162 |
| Ach, lieben Christen, seid getrost, BWV 114 | Ach. | Achabal |
| Achacachi | Achada Fazenda | Achada Furna |
| Achada Grande | Achada Leitão | Achada Monte |
| Achada Tenda | Achaea | Achaenodon |
| Achaeta | Achaetops | Achaetops pycnopygius |
| Achagua | Achaguas | Achaia |
| Achaicum Foedus | Achain | Achal Prabhala |
| Achala | Achala Basanta | Achalaïta |
| Achalpur | Achane | Achang |
| Achankovil | Achantodes | Achar |
| Achar (cràter marcià) | Acharagma | Achariaceae |
| Acharis Avtonomiuri Respublika | Acharonim | Achatina achatina |
| Achatina fulica | Achatocarpaceae | Achavalita |
| Achawa | Achères (Cher) | Achères (Yvelines) |
| Achères-la-Forêt | Achí | Achí (Bolívar) |
| Achí (Bolivar) | Achí (desambiguació) | Achís |
| Achchazu | Achd na Gàidhlig | Acheh |
| Acheilognathus | Acheilognathus asmussii | Acheilognathus barbatulus |
| Acheilognathus barbatus | Acheilognathus bergi | Acheilognathus binidentatus |
| Acheilognathus brevicaudatus | Acheilognathus chankaensis | Acheilognathus coreanus |
| Acheilognathus cyanostigma | Acheilognathus deignani | Acheilognathus elongatoides |
| Acheilognathus elongatus | Acheilognathus fasciodorsalis | Acheilognathus gracilis |
| Acheilognathus hypselonotus | Acheilognathus imberbis | Acheilognathus imfasciodorsalis |
| Acheilognathus koreensis | Acheilognathus kyphus | Acheilognathus longibarbatus |
| Acheilognathus longipinnis | Acheilognathus macromandibularis | Acheilognathus macropterus |
| Acheilognathus majusculus | Acheilognathus melanogaster | Acheilognathus meridianus |
| Acheilognathus mesembrinum | Acheilognathus microphysa | Acheilognathus omeiensis |
| Acheilognathus peihoensis | Acheilognathus polylepis | Acheilognathus polyspinus |
| Acheilognathus rhombeus | Acheilognathus signifer | Acheilognathus somjinensis |
| Acheilognathus tabira | Acheilognathus taenianalis | Acheilognathus tonkinensis |
| Acheilognathus typus | Acheilognathus yamatsutae | Achel (cervesa) |
| Achelata | Acheliata | Achelosaurus |
| Achelousaurus | Achema | Achen |
| Achenheim | Achenkoil | Achensee |
| Achern | Achernar | Achero Mañas |
| Acheron Catena | Acheron Fossae | Acheronodon |
| Acheronodon garbani | Acherontia atropos | Acherontiscidae |
| Acherontiscus | Acherontiscus caledoniae | Achery |
| Acheson | Acheta domesticus | Achetopus |
| Acheulià | Acheux-en-Amiénois | Acheux-en-Vimeu |
| Acheville | Achey | Achicourt |
| Achiel Bruneel | Achiel Buysse | Achiet-le-Grand |
| Achiet-le-Petit | Achik | Achikland |
| Achiks | Achile Battistuzzi | Achilidae |
| Achilifunk Sound System | Achill | Achill Island |
| Achill Sound | Achille | Achille Abbati |
| Achille Battistuzzi | Achille Compagnoni | Achille de Bassini |
| Achille de Broglie | Achille Devéria | Achille Emana |
| Achille Emaná | Achille Errani | Achille Essebac |
| Achille et Déidamie | Achille et Polyxène | Achille et Polyxène (òpera) |
| Achille Farines | Achille Funi | Achille Germain |
| Achille Graffigna | Achille Guenée | Achille in Sciro |
| Achille Lauro | Achille Lauro (cantant) | Achille Lauro (creuer) |
| Achille Léonce Victor Charles de Broglie | Achille Luchaire | Achille Marozzo |
| Achille Mbembe | Achille Murat | Achille Paroche |
| Achille Peri | Achille Pierre Dionis du Séjour | Achille Ratti |
| Achille Richard | Achille Rivarde | Achille Silvestrini |
| Achille Souchard | Achille Talon | Achille Tribouillet |
| Achille Valenciennes | Achille Van Acker | Achille-Félix Montaubry |
| Achillea | Achillea abrotanoides | Achillea ageratum |
| Achillea chrysocoma | Achillea clypeolata | Achillea coarctata |
| Achillea crithmifolia | Achillea millefolium | Achillea nobilis |
| Achillea ptarmica | Achillea pyrenaica | Achillea tomentosa |
| Achillea virescens | Achilles | Achilles and the Tortoise |
| Achillesaurus | Achillesaurus manazzonei | Achillobator |
| Achillobator giganticus | Achilo | Achim Hill |
| Achim Steiner | Achim von Arnim | Achimota |
| Achin | Achinoam Nini | Achinsk |
| Achiras | Achird | Achiroides leucorhynchos |
| Achiroides melanorhynchus | Achita (cràter) | Achlaena |
| Achlavda | Achlya | Achmat Dangor |
| Achmatherum | Achmed Sukarno | Achmore |
| Achnaterum hallerii | Achnatherum | Achnatherum acutum |
| Achnatherum altum | Achnatherum argenteum | Achnatherum aridum |
| Achnatherum avenoides | Achnatherum botschantzevii | Achnatherum brachychaetum |
| Achnatherum bracteatum | Achnatherum breviaristatum | Achnatherum bromoides |
| Achnatherum calamagrostis | Achnatherum capense | Achnatherum caragana |
| Achnatherum caudatum | Achnatherum chinense | Achnatherum chingii |