(of two or more people) With arms linked together; with arms around each other's shoulder or waist. / (figuratively) In collusion, in concert (with someone).

Alternative form of arm in arm

(computing) Initialism of Acorn RISC Machine or Advanced RISC Machine.

(transitive) To supply with armour or (later especially) weapons.

Abbreviation of Armenian.

Initialism of accelerated reply mail (a service of the United States Postal Service) / Initialism of adjustable rate mortgage.

The portion of the upper human appendage, from the shoulder to the wrist and sometimes including the hand. / (anatomy) The extended portion of the upper limb, from the shoulder to the elbow.

(obsolete) To take by the arm; to take up in one's arms.

(usually used in the plural) A weapon. / (in the plural) Heraldic bearings or insignia. / (in the plural, obsolete) War; hostilities; deeds or exploits of war.

(UK dialectal, chiefly Scotland) Poor; lacking in riches or wealth. / (UK dialectal, chiefly Scotland) To be pitied; pitiful; wretched.