| Acra | Accra |
| Acrab | Beta Scorpii |
| acral | acral |
| acrania | acrania |
| acrasia | acrasia |
| acre | biting |
| acrecional | accretionary |
| acrecionário | accretionary |
| acreditar | accept |
| acreditar em | believe in |
| acreditar em Deus | believe in God |
| acreditar emuiser | increase |
| acredite | believe |
| acredite se quiser | increase |
| acreditável | credible |
| acrescentado | added |
| acrescentar | add |
| acrescentar de graça | addition |
| acrescente | accrescent |
| acrescer | accrue |
| acrescível | accruable |
| acretivo | accretive |
| acreção | accretion |
| acridez | roughness |
| Acrididae | Acrididae |
| acridina | acridine |
| acrilamida | acrylamide |
| acrilato | acrylate |
| acrilonitrila | acrylonitrile |
| acrilonitrilo | acrylonitrile |
| acrimoniosamente | acrimoniously |
| acrimonioso | vitriolic |
| ACRIMSat | Active Cavity Radiometer Irradiance Monitor Satellite |
| acrimónia | acrimony |
| acrimônia | bitterness |
| acritarca | acritarch |
| acriticamente | acritically |
| acrivastina | acrivastine |
| acroasfixia | acroasphyxia |
| acrobacia | acrobatics |
| acrobacia aérea | aerobatics |
| acrobaciaaérea | acrobatics |
| acrobata | acrobat |
| acrobatao | tumblercs |
| acrobaticamente | acrobatically |
| Acrobatidae | Acrobatidae |
| acrobático | acrobatics |
| Acrocantossauro | Acrocanthosaurus |
| acrocefalia | acrocephaly |
| acrocefalosindactilia | acrocephalosyndactylia |
| Acrocephalus | Acrocephalus |
| Acrocephalus kerearako | Cook Islands Reed-warbler |
| Acrocephalus rimatarae | Rimatara Reed-warbler |
| Acrocephalus rodericanus | Rodrigues Warbler |
| Acrocephalus rufescens | Greater Swamp-warbler |
| acroceratose | acrokeratosis |
| Acrochordidae | Acrochordidae |
| acrocianose | acrocyanosis |
| Acrocomia aculeata | Acrocomia |
| acrocêntrico | acrocentric |
| acrodermatite | acrodermatitis |
| acrodermatose | acrodermatosis |
| acrodextrina | achrodextrin |
| acrodinia | acrodynia |
| acrodonte | acrodont |
| acrodínico | acrodynic |
| acrofase | acrophase |
| acrofobia | fear of heights |
| acrofonia | acrophony |
| acrofóbico | acrophobic |
| acrofónico | acrophonical |
| acrofônico | acrophonical |
| acrogeria | acrogeria |
| acrolectal | acrolectal |
| acrolecto | acrolectss |
| Acrolepiidae | Acrolepiidae |
| acroletal | acrolectal |
| acroleto | acrolect |
| acroleína | acrolein |
| acromatopsia | achromatopia |
| acromegalia | acromegaly |
| acromegálico | acromegalic |
| acromia | achromia |
| acromial | acromial |
| acromioclavicular | acromioclavicular |
| acromotriquia | achromotrichia |
| acromático | achromatic |
| acronologicamente | achronologically |
| acronológico | achronological |
| acropetal | acropetal |
| Acropomatidae | Acropomatidae |
| Acroptilon | Russian knapweed |
| acroscópico | acroscopic |
| acrosina | acrosin |
| acrossomal | acrosomal |
| acrossomo | acrosome |
| acrosticamente | acrostically |
| acrotomofilia | acrotomophilia |
| acrotério | acroterium |
| Acrux | Alpha Crucis |
| acrático | akratic |
| acréscimo | addition |
| acrílico | acrylic |
| Acrísio | Acrisius |
| acrítico | acritical |
| acrófobo | acrophobic |
| acrógeno | acrogenous |
| acrómio | acromion |
| acrópole | acropolis |
| Acrópole de Atenas | Acropolis of Athens |
| acróstico | acrostic |
| acrômio | acromion |
| acrônimo | acronym |
| Acta de Chapultepec | Inter-American Treaty of Reciprocal Assistance |
| Actaea | Actaea |
| actante | actant |
| actema | acteme |
| Actenoides concretus | Rufous-collared Kingfisher |
| Actenoides hombroni | Blue-capped Kingfisher |
| Actenoides lindsayi | Spotted Kingfisher |
| Actenoides monachus | Green-backed Kingfisher |
| Acteon | Actaeon |
| actigrafia | actigraphy |
| actina | actin |
| actinicamente | actinically |
| Actinidia | Actinidia |
| Actinidia chinensis | Actinidia chinensis |
| Actinidiaceae | Actinidiaceae |
| actinidina | actinidin |
| actinina | actinin |
| actinismo | actinism |
| actino- | actino- |
| actinobacilose | actinobacillosis |
| Actinobacteria | Actinobacteria |
| actinobactéria | actinobacterium |
| Actinocladum | Actinocladum verticillatum |
| actinolita | actinolite |
| actinolite | actinolite |
| actinolito | actinolite |
| actinologia | actinology |
| actinolítico | actinolitic |
| actinometria | actinometry |
| actinomiceta | actinomycete |
| actinomicina | actinomycin |
| actinomicose | actinomycosis |
| actinomicótico | actinomycotic |
| actinomorfo | actinomorphic |
| actinométrico | actinometric |
| Actinopterygii | Actinopterygii |
| actinopterígio | actinopterygian |
| actinorriza | actinorhiza |
| actinostelo | actinostele |
| actinostélico | actinostelic |
| actinoterapia | actinotherapy |
| actinídeos | actinide |
| Actinídio | Actinide |
| actinógrafo | actinograph |
| actinómetro | actinometer |
| actinômetro | actinometer |
| Action Française | Action Française |
| ActionScript | ActionScript |
| Active Directory | Active directory |
| Active Virus Shield | AOL Active Virus Shield |
| ActiveX | Component Object Model |
| Actividade | Buoyancy |
| actividade sísmica | seismic activity |
