| Achilles | Academy Award | Accessible computing |
| AcidFor alternative meanings see acid (disambiguation). An acid (represented by the generic formula AH is typically a water-soluble, sour-tasting chemical compound. An acid always has a pH of less than 7. It is a molecule or ion that contains hydrogen or that | ActinopterygiiSee text The Actinopterygii are the ray-finned fish . They are the dominant group of vertebrates, with over 27,000 species ubiquitous throughout fresh water and marine environments. They are traditionally treated as a subclass of the Osteichthyes, or bony | ActorAn actor is a person who acts, or plays a role in an artistic production. The term commonly refers to someone working in movies, television, live theatre, or radio, and can occasionally denote a street entertainer. Besides playing dramatic roles, actors m |
| ActiniumActinium is a chemical element in the periodic table that has the symbol Ac and atomic number 89. Notable characteristics Actinium is a silvery radioactive metallic element. Due to its intense radioactivity, Actinium glows in the dark with an eerie blue l | Acute disseminated encephalomyelitisAcute disseminated encephalomyelitis ADEM is an immune mediated disease of brain. It usually occurs following a viral infection or vaccination, but it may also appear spontaneously. There are multiple inflammatory cell deposits in the brain, particularly | Achill IslandAchill Island in County Mayo is the largest island off the Irish mainland, and is situated off the west coast. Achill is attached to the mainland by a bridge between the villages of Achill Sound and Achill, so it is possible to drive onto the island. |
| AccordionAn accordion is a small portable free-reed wind instrument with a keyboard, the smallest representative of the organ family. Sound is made by a thin metal ribbon, a reed, that is held at one end and free at the other, like a ruler on the edge of a table t | AcousticsAcoustics is a branch of physics and is study of sound, mechanical waves in gases, liquids, and solids. A scientist who works in the field of acoustics is an acoustician . The application of acoustics in technology is called acoustical engineering. There | ActaeonIn Greek mythology, Actaeon or Aktaion was a son of Aristaeus and Autonoe in Boeotia, a hunter who endured the wrath of Diana. Diana was bathing nude in the woods near Boeotian Orchomenos when the hunter Actaeon stumbled across her. He stopped and stared, |
| Acoustic theory | Active recall | Acacia |
| Acapulco | Acropolis | Acupuncture |
| Acetylene | Acre | Actium |
| Acquire | Acetone | Actinophryid |
| Achaeans | Acting | Act of Settlement 1701 |
| Acropolis, Athens | Acorn Electron | Acts of the Apostles |
| Academic elitism | Accidental properties | Acadia University |
| Acoustic guitar | Activism | Accusative case |
| Actinide | ACN | Accelerated Graphics Port |
| Acceleration | Action Against Hunger | Acantharea |
| Accountancy | Acquis | ACE inhibitor |
| Active Directory | Acrylic paint | Active Server Pages |
| Ackermann function | Act of Union 1707 | Acid-base reaction theories |
| Accrington | Accumulator | AC-130 gunship |
| ACF Fiorentina | Achduart | Achiltibuie |
| Acceptance test | Acid rain | Acephalous |
| Acephali | Ace-to-six low | Ace-to-five low |
| Activision | Activation energy | Accelerating universe |
| Academy of Motion Picture Arts and Sciences | Acetic acid bacteria | Accidental |
| Access | Access charge | Access control |
| Access denial | Access failure | Access time |
| Acknowledgement | Acoustic coupler | Acquisition |
| Active laser medium | Accrual bond | Accuracy and precision |
| Acupressure | Accusative | Acetic acid |
| Acanthocephala | Actuary | Action movie |
| Acadian | Academy Award for Short Film - Novelty | Academy Award for Best Title Writing |
| Academy Award for Best Short Film - Live Action - 2 Reels | Academy Award for Best Dance Direction | Academy Award for Best Assistant Director |
| Academy Award for Best Short Film - Color | ACIS | Accuracy in Media |
| Academy Award for Best Story | Action | Acme |
| Acetylcholine | Acerola | Academia operosorum Labacensis |
| Academy Award for Best Actor | Act Prohibiting Importation of Slaves | Acrochordon |
