Old Irish word arm comes from Proto-Indo-European *h₂r̥-ti-
You can also see our other etymologies for the Old Irish word arm.
|arma||Latin (lat)||(Late Latin) weapon. (pluralonly) defence. (pluralonly) defensive arms, armor/armour, shields, weapons of war.. (pluralonly) soldiers, military power. (pluralonly) tools. (pluralonly) war.|
|arm||Old Irish (sga)|