| ActivePython | ActiveRecord | ActiveState |
| ActiveState Komodo | ActiveState Komodo Edit | ActiveState Komodo IDE |
| ActiveState Tool | ActiveSync | Activesync |
| ActiveVirusShield | ActiveX | Activia |
| Activision | Activision Blizzard | Activision Inc |
| Activision Value | Activity Based Costing | Activity-based costing |
| Acton Vale | Actophilornis africana | Actor (UML) |
| Actor sequitur forum rei | Actore non probante reus absolvitur | Actovegin |
| ActRaiser | ActRaiser 2 | Acts of Vengeance |
| Actu | Actually | Actum atque tractatum |
| Actum est ilicet! | Actum ut supra | Actus fidei |
| Actus purus | ACTUV | ACTV |
| Actyon Sports | ACube Systems | Aculeata |
| Aculeola | Aculeola nigra | Aculops |
| Aculus | ACUM | Acumen |
| Acumen Fund | Acumen Fund, Inc. | Acupalpus |
| Acura | Acura CL | Acura Classic |
| Acura Classic Los Angeles | Acura Classic San Diego | Acura ILX |
| Acura Legend | Acura MDX | Acura NSX |
| Acura RDX | Acura RL | Acura RLX |
| Acura RSX | Acura SLX | Acura TL |
| Acura TLX | Acura TSX | Acura Vigor |
| Acura ZDX | Acutalini | Acutalis |
| Acutalis balteata | Acutalis binaria | Acutalis flaviventris |
| Acutalis illinoiensis | Acutalis lucidus | Acutalis lugubrina |
| Acutalis moesta | Acutalis plagiata | Acutalis semipallida |
| Acutalis tripunctata | Acutalis variabilis | Acutandra araucana |
| Acutandra degeerii | Acutandra murrayi | Acutandra punctatissima |
| Acutaspis aurantii | Acutaspis litorana | Acuticauda |
| Acutifrons australis | Acutifrons caracarensis | Acutodorcadion |
| Acutosiphon | Acuvue | Acxiom |
| Acyntha | Acyrhosiphon | Acyrthosiphon |
| Acyrthosiphon gossypii | Acyrthosiphon pisum | Acyrthosiphon solani |
| Acyrtosiphon | Acytolepis lilacea | Acytota |
| AD | Ad | Ad absurdum |
| Ad acta | Ad aeternum | Ad Apostolorum Principis |
| Ad aras | Ad arbitrium | Ad astra per aspera |
| Ad augusta per angusta | Ad aware | Ad bestias |
| Ad bestias! | Ad Calendas Graecas | Ad calendas graecas |
| Ad captandum benevolentiam | Ad captandum vulgus | Ad cogitandum et agendum homo natus est |
| Ad delectandum | Ad discendum, non ad docendum | Ad disputandum |
| Ad ea debeat adaptari jus, quae frequenter eveniunt | Ad exemplum | Ad extirpanda |
| Ad extra | Ad extremitates | Ad finem |
| Ad fontes | Ad futarum memoriam | Ad futarum rei memoriam |
| Ad Gentes | Ad gloriam | Ad gustum |
| Ad gustus | Ad hastam | Ad Herculis columnas |
| Ad hoc | Ad hoc (значения) | Ad hoc On-Demand Distance Vector Routing |
| Ad hoc полиморфизм | Ad hominem | Ad hominem circumstantiae |
| Ad hominem tu quoque | Ad honores | Ad hoste maligno libera nos, Domine |
| Ad impossibilia nemo tenetur | Ad infinitum | Ad informandum |
| Ad instar | Ad instruendum | Ad interim |
| Ad latus | AD Leonis | Ad Lib |
| Ad lib | Ad Liberum | Ad libita librarii |
| Ad libitum | Ad Libitum | Ad Libitum (группа) |
| Ad Libitum (группа, Екатеринбург) | Ad libitum (значения) | Ad litem |
| Ad litteram | Ad loca! | Ad maiorem Dei gloriam |
| Ad majorem | Ad majorem Dei gloriam | Ad majorem dei gloriam |
| Ad majorem gloriam | Ad Majorem Sathanas Gloriam | Ad manum |
| Ad Marginem | Ad Marginem (издательство) | Ad maximum |
| Ad meliora tempora | Ad meliorem | Ad Melpomenem |
| Ad memorandum | Ad minimum | Ad modum |
| Ad multus annos | Ad Muncher | Ad narrandum, non ad probandum |
| Ad nauseam | Ad normam | Ad notam |
| Ad notanda | Ad notata | Ad oculos |
| Ad opus! | Ad patres | Ad patres conscriptos |
| Ad perpetuam rei memoriam | Ad personam | Ad Petri Cathedram |
| Ad pias causas | Ad pluralitatem votorum | AD Police |
| AD Police - To Protect and Serve | AD Police: To Serve and Protect | Ad publicandum |
| Ad ratificandum | Ad referendum | Ad rem |
| Ad se ipsum | Ad Sinarum Gentem | Ad totalem evaporabionem |
| Ad unguem | Ad unum omnes | Ad usum |
| Ad usum Delphini | Ad usum delphini | Ad usum externum |
| Ad usum internum | Ad usum populi | Ad usum proprium |
| Ad usum vitae | Ad valorem | Ad verbum |
| Ad verbum audiendum | Ad vitam | Ad vitam aeternam |
| Ad vitam aut culpam | Ad vocem | AD Льва |
| AD&D | AD-AS | Ad-Aware |
| Ad-gio | Ad-hoc | Ad-hoc On-demand Distance Vector |
| AD-mix | Ad-Rock | Ad.Br. |
| AD/HD | Ada | AdA |
| ADA | Ada (язык программирования) | ADA Aerospace |
| Ada Brown | Ada County, Idaho | AdaBoost |
| ADAC | ADAC Berlin-Brandenburg | ADAC Formel 4 |
| ADAC Formel Masters | ADAC Формула-4 | ADAC Формула-Мастер |
| Adachi-ga Hara | Adachia | Adactylus |
| Adagio | Adagio (band) | Adagio (группа) |
| Adagio for Strings | Adair County, Iowa | Adair County, Kentucky |
| Adair County, Missouri | Adalia | Adalia bipunctata |
| ADAM | Adam | Adam & the Ants |
| Adam Ahmed R. Gemili | Adam and the Ants | Adam Ant |
| ADAM Audio | Adam Baldwin | Adam Bartlett |
| Adam Bell, Clim of the Clough and William of Cloudesley | Adam Bernard Mickiewicz | Adam Bernstein |
| Adam Blythe | Adam Brody | Adam Charles Goldberg |
| Adam Cheng | Adam Cheng Siu-Chow | Adam Clayton |
| Adam Copeland | Adam David Lallana | Adam David Willard |
| Adam Drury | Adam Federici | Adam Forshaw |
| Adam Frans van der Meulen | Adam G. Sevani | Adam Gregory II |
| Adam Griffiths | Adam Grinberg | Adam Hammill |
| Adam Hansen | Adam in Chains | Adam Irigoyen |
| Adam Jarubas | Adam Jezierski | Adam Johansson |
