| acronimo | Abkürzung |
| Acronimo ridondante | Redundantes Akronym |
| acropoli | Akropolis |
| Acropoli di Atene | Akropolis |
| Across the Universe | Across the Universe |
| acrostico | Akrostichon |
| Acroterio | Akroterion |
| acroto | Skrotum |
| Acrux | Acrux |
| Act of Settlement | Act of Settlement |
| Acta Apostolicae Sedis | Acta Apostolicae Sedis |
| acte | Tat |
| Actea | Claudia Acte |
| Actinia equina | Pferdeaktinie |
| Actiniaria | Seeanemonen |
| Actinidia chinensis | Kiwifrucht |
| Actinobacteria | Actinobacteria |
| actinolite | Aktinolith |
| Actinomyces | Actinobacteria |
| Actinopterygii | Strahlenflosser |
| Actio libera in causa | Actio libera in causa |
| Action | Handlung |
| Action Directe | Action Directe |
| Action figure | Action-Figur |
| Action Française | Action française |
| Action Learning | Action Learning |
| Action painting | Action Painting |
| Action Replay | Action Replay |
| Action RPG | Action-Rollenspiel |
| Actions per minute | Aktionen pro Minute |
| ActionScript | ActionScript |
| Actitis hypoleucos | Flussuferläufer |
| Active Cavity Radiometer Irradiance Monitor Satellite | ACRIMSat |
| Active Directory | Active Directory |
| Active Server Pages | Active Server Pages |
| ActiveX | Component Object Model |
| Activity Based Costing | Prozesskostenrechnung |
| Activity diagram | Aktivitätsdiagramm |
| Acton Vale | Acton Vale |
| acufene | Tinnitus |
| Acuita visiva | Sehschärfe |
| acuità uditiva | Hörschärfe |
| Aculeata | Stechimmen |
| aculeo | Stachel |
| acume | Intelligenz |
| acuminato | scharf |
| acupuntura | Akupunktur |
| Acura | Acura |
| Acusilao | Akusilaos von Argos |
| acustica | Akustik |
| Acustica architettonica | Raumakustik |
| acusticamente | akustisch |
