Arm: English has two completely unrelated… | etymologist.ai
arm
/ɑːɹm/·noun·before 900 CE·Established
Origin
From OldEnglish 'earm,' PIE *h₂er-mo- (the jointed thing) — named for its articulations, entirely unrelated to 'arms' (weapons) from Latin.
Definition
Each of the two upper limbs of the human body from the shoulder to the hand.
The Full Story
Proto-Germanicbefore 900 CEwell-attested
From OldEnglish 'earm' (arm, the upper limb), from Proto-Germanic *armaz, from PIE *h₂er-mo-, a derivative of *h₂er- (to fit together, to join, to attach). The arm was named as 'the jointed thing' — the limb defined by its articulation at shoulder and elbow, the place where bones fit together. The samePIE root *h₂er- produced Latin 'armus' (shoulder, upper arm), 'artus' (joint, limb, narrow), 'articulāre' (to divide into joints, to articulate), 'ars, artis' (skill, art — originally the fitting-together of
), and Greek 'arthron' (joint, whence 'arthritis,' inflammation of the joints) and 'arariskein' (to fit together). The semantic range of *h₂er- — from physical
. English thus has two homonyms: the body part (Germanic inheritance) and weaponry (Latin borrowing), which may ultimately trace to the same PIE root through different paths. Cognates for the body part include Old Frisian 'erm,' Old Saxon 'arm,' Old High German 'arm,' Old Norse 'armr,' Gothic 'arms,' Latin 'armus,' and Sanskrit 'īrmā' (arm, forearm). Key roots: *h₂er- (Proto-Indo-European: "to fit, to join").