aquatic
ADJECTIVE An aquatic animal or plant lives in water.
aqueduct aqueducts
NOUN a bridge with many arches, which carries a water supply over a valley
arable
ADJECTIVE Arable land is used for growing crops.
arc arcs
NOUN 1 a smoothly curving line
2 In geometry, an arc is a section of the circumference of a circle.
arcade arcades
NOUN a covered passageway where there are shops or market stalls
arch arches, arching, arched
NOUN 1 a structure that has a curved top, supported on either side by a pillar or wall
VERB 2 If something arches, or if you arch it, it forms a curved line or shape. • The cat arched its back.
archaeology; also spelt archeology
NOUN the study of the past by digging up and examining the remains of things such as buildings, tools, and pots
[from Greek arkhaios meaning ancient]
archbishop archbishops
NOUN a bishop of the highest rank in a Christian Church • the Archbishop of Canterbury
archery
NOUN a sport in which people shoot at a target with a bow and arrow
architect architects
NOUN a person who designs buildings
architecture
NOUN the art or practice of designing buildings
arctic
NOUN 1 The Arctic is the region north of the Arctic Circle.
ADJECTIVE 2 very cold indeed • You need specially warm clothes for arctic conditions.
are
VERB a present tense of be
area areas
NOUN 1 a particular part of a place, country, or the world • a built-up area of the city
SYNONYMS: district, region, zone
2 the measurement of a flat surface • The area of the playground is 1500 square metres (1500 m2).
arena arenas
NOUN a place where sports and other public events take place
[from Latin harena meaning sand, because of the sandy centre of an amphitheatre where gladiators fought]
aren’t
VERB a contraction of are not
argue argues, arguing, argued
VERB 1 If you argue with someone about something, you disagree with them about it, sometimes in an angry way.
2 If you argue that something is true, you give reasons why you think that it is.
argument arguments
NOUN a talk between people who do not agree
arid
ADJECTIVE Arid land is very dry because there has been very little rain.
ANTONYM: fertile
arise arises, arising, arose, arisen
VERB When something such as an opportunity or a problem arises, it begins to exist.
aristocrat aristocrats
NOUN someone whose family has a high social rank, and who has a title such as Lord or Lady
aristocratic ADJECTIVE aristocracy NOUN
arithmetic
NOUN the part of mathematics that is to do with the addition, subtraction, multiplication and division of numbers
[from Greek arithmos meaning number]
arithmetical ADJECTIVE
arithmetically ADVERB
arm arms, arming, armed
NOUN 1 the part of your body between your shoulder and your wrist
PLURAL NOUN 2 Arms are weapons used in a war.
VERB 3 If a country arms itself, it prepares for war.
armada armadas
NOUN a large fleet of warships • The Spanish Armada was the fleet sent to destroy the English in 1588.
armchair armchairs
NOUN a large chair with a support on each side for your arms
armistice armistices
NOUN In war, an armistice is an agreement to stop fighting.
armour
NOUN 1 In the past, armour was metal clothing worn for protection in battle.
2 In modern warfare, tanks are often referred to as armour.
army armies
NOUN a large group of soldiers who are trained to fight on land
aroma aromas
NOUN a strong, pleasant smell
[a Greek word meaning spice]
aromatic ADJECTIVE
around
PREPOSITION 1 situated at various points in a place or area • There are several post boxes around the town.
2 from place to place inside an area • We walked around the stalls at the summer fair.
3 surrounding or encircling a place or object • We were sitting around the table.
4 at approximately the time or place mentioned • The jumble sale began around noon.
arrange arranges, arranging, arranged
VERB 1 If you arrange to do something, or arrange something for someone, you make plans for it or make it possible. • I arranged to meet him later. • Dad arranged a trip to the circus for us.
2 If you arrange objects, you set them out in a particular way. • We arranged the books in alphabetical order.
array arrays
NOUN 1 a large number of different things displayed together
2 a mathematical way of grouping. For example, 3 × 2 is shown as ::: and 2 × 3 is shown as ⋮⋮.
arrest arrests, arresting, arrested
VERB 1 If the police arrest someone, they take them to a police station because they believe they may have committed a crime.
NOUN 2 An arrest is the act of arresting someone.
arrive arrives, arriving, arrived
VERB 1 When you arrive at a place, you reach it at the end of your journey.
2 When you arrive at a decision you make up your mind.
arrival NOUN
arrogant
ADJECTIVE Arrogant people behave as if they are better than other people.
arrow arrows
NOUN a long, thin weapon with a sharp point at one end, shot from a bow
arsenal arsenals
NOUN a place where weapons and ammunition are stored or produced
arsenic
NOUN a strong, dangerous poison that can kill
arson