Collins COBUILD Advanced Learner’s Dictionary

1 N‑COUNT An arbiter is a person or institution that judges and settles a quarrel between two other people or groups. [FORMAL ] □  He was the ultimate arbiter on both theological and political matters.

2 N‑COUNT An arbiter of taste or style is someone who has a lot of influence in deciding what is fashionable or socially desirable. [FORMAL ]

ar|bi|trage /ɑː ^r b I trɑːʒ/ N‑UNCOUNT [oft N n] In finance, arbitrage is the activity of buying shares or currency in one financial market and selling it at a profit in another. [BUSINESS ]

ar|bi|tra|ger /ɑː ^r b I trɑːʒɜː ^r / (arbitragers ) also arbitrageur N‑COUNT In finance, an arbitrager is someone who buys currencies, securities, or commodities on one country's market in order to make money by immediately selling them at a profit on another country's market. [BUSINESS ]

ar|bi|trary /ɑː ^r b I tri, [AM ] -treri/ ADJ If you describe an action, rule, or decision as arbitrary , you think that it is not based on any principle, plan, or system. It often seems unfair because of this. [DISAPPROVAL ] □  Arbitrary arrests and detention without trial were common. ●  ar|bi|trari|ly /ɑː ^r b I treə r I li/ ADV [ADV with v] □  The victims were not chosen arbitrarily.

ar|bi|trate /ɑː ^r b I tre I t/ (arbitrates , arbitrating , arbitrated ) VERB When someone in authority arbitrates between two people or groups who are in dispute, they consider all the facts and make an official decision about who is right. □ [V + between ] He arbitrates between investors and members of the association. □ [V ] The tribunal had been set up to arbitrate in the dispute. ●  ar|bi|tra|tor /ɑː ^r b I tre I tə ^r / (arbitrators ) N‑COUNT □  He served as an arbitrator in a series of commercial disputes in India.

ar|bi|tra|tion /ɑː ^r b I tre I ʃ ^ə n/ N‑UNCOUNT [oft N n] Arbitration is the judging of a dispute between people or groups by someone who is not involved. □  The matter is likely to go to arbitration.

ar|bor|eal /ɑː ^r bɔː riəl/

1 ADJ [usu ADJ n] Arboreal animals live in trees. [TECHNICAL ] □  …arboreal marsupials which resemble monkeys.

2 ADJ [usu ADJ n] Arboreal means relating to trees. [FORMAL ] □  …the arboreal splendor of the valley.

ar|bo|retum /ɑː ^r bəriː təm/ (arboreta /ɑː ^r bəriː tə/ or arboretums ) N‑COUNT An arboretum is a specially designed garden of different types of trees.

ar|bour /ɑː ^r bə ^r / (arbours ) in AM, use arbor N‑COUNT An arbour is a shelter in a garden which is formed by leaves and stems of plants growing close together over a light framework.

arc /ɑː ^r k/ (arcs )

1 N‑COUNT An arc is a smoothly curving line or movement. □  The Aleutian chain is a long arc of islands in the North Pacific.

2 N‑COUNT In geometry, an arc is a part of the line that forms the outside of a circle. [TECHNICAL ]

ar|cade /ɑː ^r ke I d/ (arcades ) N‑COUNT An arcade is a covered passage where there are shops or market stalls. □  …a shopping arcade.

ar|ca de game (arcade games ) N‑COUNT An arcade game is a computer game of the type that is often played in amusement arcades.

ar|cane /ɑː ^r ke I n/ ADJ Something that is arcane is secret or mysterious. [FORMAL ] □  Until a few months ago few people outside the arcane world of contemporary music had heard of Gorecki.

arch /ɑː ^r tʃ/ (arches , arching , arched )

1 N‑COUNT An arch is a structure that is curved at the top and is supported on either side by a pillar, post, or wall.

2 N‑COUNT An arch is a curved line or movement.

3 N‑COUNT The arch of your foot is the curved section at the bottom in the middle.

4 VERB If you arch a part of your body such as your back or if it arches , you bend it so that it forms a curve. □ [V n] Don't arch your back, keep your spine straight. [Also V ]