אָדער 2
־ן
די/דער
'vein'

ETYMOLOGY

{DW² notes that the original meaning in German was any vessel or ligament in the body: sinew, muscle, intestine, tissue. Thanks to the influence of medieval medicine and the teachings of Hippocrates about the four humors and the use of blood-letting to restore their "balance", the meaning 'vein' came to dominate. Kluge/Seebold write that the narrowing of the meaning to 'vein' only arose in NHG, probably to differentiate it from Nerv 'nerve' and Sehne 'sinew'. Yiddish lacks a cognate to Sehne, still the meaning has been narrowed in Yiddish as well. Perhaps the role Jews played as doctors had an influence?}
ON æðr 'vein', OE ǣdre 'river; vein, artery; nerve, siney; kidney', OS -āđara, Dutch ader 'vein', OHG ād(a)ra 'vein, sinew, muscle', MHG âder, NHG Ader 'sinew, (pl.) bowels' > PGmc ✱ēþrō- ~ ✱ēdrō- 'vein, rivulet' (or ✱ǣd(a)rō); from PIE ✱h₁eh₁t-r- (perhaps originally a mobile paradigm: ✱h₁éh₁t-r-, (pl.) ✱h₁h₁t-ṓr-) (or from ✱ēt-r- or ✱ēter-); perhaps the same root as ✱eþman- ~ ✱ēdman- 'breath' (seet אָטעם).
Related: Greek ἦτορ 'heart', ἦτρον 'belly'
{DW² 1: 1476; Kluge/Seebold 2011: 16; Kroonen 2013: 120}
Vowel 12, Proto-Yiddish ✱ɔ̄

WESTERN

Old Literary Yiddish (ca. 1100-1800)

אודרן {מרכּבֿת המשנה, קראָקע 1534}

ṓdər {NORTHWESTERN, Katz 1982: 286}

Holland (Netherlands)

ôder {HOLLAND, Beem, Jerosche}

Oyberland (West Transcarpathian)

óˑdər lɔzn אָדער לאָזן {WTCP, Vác, 47197}

CENTRAL

údər {Katz 1982: 286}

NORTHEASTERN

ɔ́dər {Katz 1982: 286}