Meaning

verb prepare oneself for a military confrontation

verb supply with arms

adjective (used of persons or the military) characterized by having or bearing arms

originEtymology tree Proto-Indo-European *h₂er- Proto-Indo-European *h₂érmos Proto-Germanic *armaz Proto-West Germanic *arm Old English earm Middle English arm English arm English -ed English armed From arm (“the upper limb of the body”) + -ed.

Etymology from Wiktionary, CC BY-SA 3.0