aptoteA noun (broadly speaking) which has no distinction of cases; an indeclinable noun.
AquaterraCollectively, all the submerged lands that were once above water in ice age glacial periods, since the start of the Pleistocene.
AquilonThe Roman god of the North Wind, equivalent to the Greek god Boreas.
-arOf, near, or pertaining to; adjective suffix appended to various words, often nouns, to make an adjective form. Often added to words of Latin origin, but used with other words also.
ArachosiaAn ancient Achaemenid and Seleucid satrapy in the eastern part of their respective empires, around modern-day southern Afghanistan.
ArgolicRelating to Argolis (various subdivisions which such name) in the Peloponnesus.
Argo NavisA former constellation of the southern sky, said to represent the mythical ship Argo. In 1763, it was divided into the three new constellations: Carina (keel), Puppis (stern), and Vela (sail).
argumentum ad baculumThe use or threat of force to coerce acceptance of an argument.
argumentum ad consequentiamA logical fallacy in which a statement is determined to be true or false based on whether it would be pleasant or desirable, rather than based on reality.
argumentum ad hominemA type of fallacious argument in which the attempt is made to refute a theory or belief by discrediting the person(s) who advocate that theory or belief; an ad hominem argument.
argumentum ad ignorantiamA fallacious argument asserting that a proposition is true because it has not yet been proven false, or vice versa.
arreptitiousPossessed; raving; isolated from reality.
arrhaMoney or some other valuable item given to evidence a contract; a pledge or earnest.
ArsacesThe dynastic name of several Parthian and Armenian kings of the Arsacid dynasty.
ArsacidOf or pertaining to the Parthian dynasty established by Arsaces I which ruled the Parthian Empire during 247 BC – 224 AD, Armenia during 54–428, as well as Iberia and Caucasian Albania
ArsamosataAn ancient city situated on the bank of the Murat River (called the Arsanias in classical sources), near the present-day city of Elazığ in Turkey.
ars antiquaThe medieval music of Europe during the High Middle Ages, between approximately 1170 and 1310.
ars novaA musical style that flourished in the Kingdom of France and its surroundings during the Late Middle Ages, particularly between the preparation of the Roman de Fauvel (1310s) and the death of composer Guillaume de Machaut in 1377.
Asia MinorA large peninsula, mostly coterminous with Anatolia, between the Mediterranean Sea, the Aegean Sea and the Black Sea; it makes up the Asian part of Turkey.
asinarySynonym of asinine (“ass-like, donkey-like, in sutbbornness, foolishness, or other ways”).
asperitasA cloud formation characterized by wavy undulations in the cloud base.