-ar

WordReference Random House Learner's Dictionary of American English © 2025

-ar,¹ 

1. suffix. 
   • -ar is attached to some nouns (many of which have an l before the end) to form adjectives: circle + -ar → circular;
     single + -ar → singular.
   • -ar is also attached to some verbs to form nouns with the meaning "one who does or performs an act of'': beg + -ar → beggar;
     lie + -ar → liar.

AR,  an abbreviation of:

1. Arkansas.

A/R,  an abbreviation of:

1. Business accounts receivable.

Collins Concise English Dictionary © HarperCollins Publishers::

-ar suffix:forming_adjectives

1. of; belonging to; like: linear, polar, minuscular

Etymology: via Old French -er from Latin -āris, replacing -ālis ( -al¹) after stems ending in l

WordReference Random House Unabridged Dictionary of American English © 2025

ar- ,

1. var. of ad- before
   r: arrear.

-ar¹ ,

1. var. of the adjective-forming suffix -al¹, joined to words in which an l precedes the suffix:
   circular;
   lunar;
   singular.

• Latin -āris
• Anglo-French, Old French
• Latin -āris; replacing Middle English -er

-ar² ,

1. var. of -er², often under the influence of a spelling with -ar- in a cognate Latin noun:
   burglar;
   collar;
   mortar;
   poplar;
   scholar;
   vicar;
   vinegar.

-ar³ ,

1. var. of -er¹ on the model of -ar², used in the formation of nouns of agency:
   liar; beggar.

AR ,

1. Business annual return.
2. Arkansas (approved esp. for use with zip code).
3. Military Army Regulation;
   Army Regulations.

Ar ,

1. Chemistry, Language Varieties Arabic.

Ar ,[Symbol, Chem.]

1. argon.

Ar. ,

1. Arabic.
2. Aramaic.

ar. ,

1. arrival.
2. arrive;
   arrives.

A/R ,

1. Business account receivable.
2. Business accounts receivable.

Also, a/r 
A.R. ,

1. Business annual return.
2. Military Army Regulation;
   Army Regulations.

a.r. ,

1. Business [Insurance.] all risks.