| Term | Definition |
| apothegm | n. pithy, compact saying |
| apotheosis | n. elevation to godhood; an ideal example of something |
| appall | v. dismay; shock |
| apparition | n. ghost; phantom |
| *appease | v. pacify or soothe; relieve |
| appellation | n. name; title |
| append | v. attach |
| application | n. diligent attention |
| application | v. apply |
| apposite | adj. appropriate; fitting |
| appraise | v. estimate value of |
| appreciate | v. be thankful for; increase in worth; be thoroughly conscious of |
| apprehend | v. arrest (a criminal); dread; perceive |
| apprehensive | adj. fearful; discerning |
| *apprise | v. inform |
| *approbation | n. approval |
| *appropriate | v. acquire |
| appurtenances | n. subordinate possessions |
| apropos | prep. with reference to; regarding |
| aptitude | n. fitness; talent |
| aquiline | adj. curved, hooked |
| arable | adj. fit for growing crops |
| arbiter | n. person with power to decide a matter in dispute; judge |
| arbitrary | adj. unreasonable or capricious; tyrannical |
| arbitrate | v. act as judge |
| arboretum | n. place where different varieties of trees and shrubs are studied and exhibited |
| arcade | n. a covered passageway, usually lined with shops |
| arcane | adj. secret; mysterious; known only to the initiated |
| archaeology | n. study of artifacts and relics of early mankind |
| archaic | adj. antiquated |
| archetype | n. prototype; primitive pattern |
| archipelago | n. group of closely located islands |
| archives | n. public records; place where public records are kept |
| ardor | n. heat; passion; zeal |
| arduous | adj. hard; strenuous |
| argot | n. slang |
| aria | n. operatic solo |
| arid | adj. dry; barren |
| aristocracy | n. hereditary nobility; privileged class |
| armada | n. fleet of warships |
| aromatic | adj. fragrant |
| arraign | v. charge in court; indict |
| arrears | n. being in debt |
| arrhythmic | adj. lacking rhythm or regularity |
| arrogance | n. pride haughtiness |
| arroyo | n. gully |
| arsenal | n. storage place for military equipment |
| articulate | adj. effective; distinct |
| artifact | n. object made by human beings, either handmade or mass produced |
| artifice | n. deception; trickery |
| artisan | n. a manually skilled worker |
| *artless | adj. without guile |
| ascendancy | n. controlling influence |
| *ascetic | adj. practicing self-denial; austere |
| ascribe | v. refer; attribute; assign |
| aseptic | adj. preventing infection |
| ashen | adj. ash-colored; deadly pale |
| asinine | adj. stupid |
| askance | adv. with a sideways or indirect look |
| askew | adv. crookedly; slanted; at an angle |
| asperity | n. sharpness of temper |
| aspersion | n. slanderous remark |
| aspirant | n. seeker after position or status |
| aspire | v. seek to attain; long for |
| assail | v. assault |
| assay | v. analyze; examine |
| assent | v. agree; accept |
| assert | v. state strongly or positively; insist on or demand recognition of |
| assessment | n. estimation; appraisal |
| *assiduous | adj. diligent |
| assimilate | v. absorb; cause to become homogeneous |
| *assuage | v. ease or lessen (pain); satisfy (hunger); soothe (anger) |
| assumption | n. something taken or granted; the taking over or taking possession of |
| assurance | n. promise or pledge; certainty; self confidence |
| asteroid | n. small planet |
| astigmatism | n. eye defect that prevents proper focus |
| array | v. clothe; adorn |
| array | v. marshal; draw up in order |