This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. One chosen or appointed to judge or decide a disputed issue; an arbitrator.

n. One who has the power to judge or ordain at will: an arbiter of fashion. See Synonyms at judge.

n. A person appointed, or chosen, by parties to determine a controversy between them; an arbitrator.

n. A person or object having the power of judging and determining, or ordaining, without control; one whose power of deciding and governing is not limited.

v. To act as arbiter.

n. A person appointed, or chosen, by parties to determine a controversy between them.

n. Any person who has the power of judging and determining, or ordaining, without control; one whose power of deciding and governing is not limited.

v. To act as arbiter between.

n. A person chosen by the parties in a controversy to decide their differences; one who decides points at issue; an arbitrator; a referee; an umpire.

n. In a general sense, a person who has the power of judging and determining absolutely according to his own pleasure; one whose power of deciding and governing is not limited; one who has a matter under his sole authority for adjudication.

To act as arbiter between; judge.

n. someone chosen to judge and decide a disputed issue

n. someone with the power to settle matters at will

"While inviting Iran to the upcoming conference on Afghanistan seems like a prudent move — engaging Iran first on a key area of mutual concern rather than going after the big issues outright — it’s important to remember that Khamenei is the main arbiter of Iran’s foreign policy."

expert   

arbiterelegantiarum   

umpire    referee    governor    arbitrator    controller    director    ruler    judge    mastery   

arbitrator    umpire    mediator    lawgiver    arbitration    referee    tribunal    executor    arbitrament