(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.

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

(sometimes in combination) Equipped, especially with a weapon. / (of a weapon) Prepared for use; loaded. / (obsolete) Furnished with whatever serves to add strength, force, or efficiency.

simple past tense and past participle of arm

(chiefly in combination) Having an arm or arms, often of a specified number or type. / (of a creature) Possessing arms of a specified number or type.

Abbreviation of Armenian.

The amount an arm or arms can hold.

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

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

present participle of arm