PWS

*ḏirāˁ- - arm, elbow (SED I 65, Kogan 2011: 224)

The traditional derivation from *ḏrˁ ‘to sow’ (Fronzaroli 1964:34, 48 and 1969:9) is difficult to prove

Akkadian
durāˀu - arm, foreleg (CAD D 190, AHw. 177)

d­ instead of the expected z­ suggests a borrowing from Arm.; in this case -­u of the first syllable would reflect early Arm. *-­u­, the vocalism possibly confirmed by the Amarna form  (SED I No. 65, Abraham–Sokoloff 2011:29).

Ugaritic
ḏrˁ - arm (DUL 288)
Amarna Canaanite
zu-ru-uḫ - arm (DNWSI 342)
Hebrew
zərōaˁ - arm (HALOT 280)
Syriac
drāˁā - arm; forequarter; side brace; elbow (LSyr. 168, SL 324)
Mandaic
dra - arm (MD 114)
Maalula
ḏrōˁa - Arm (GNDM 22)
Arabic
ḏirāˁ- - forearm (BK 1 770, Lane 961)
Geez
mazrāˁt - arm, shoulder (CDG 379)
Tigre
mäzrəˁət - arm, yard (WTS 496)
Tigre
zäraˁ - arm (WTS 496)
The word may either reflect an original pattern lost elsewhere in Eth. or be an Arabism (with -ä- vs. Arb. -i-?).
Tigrinya
mäzraˁǝt - arm (TED 490, CDG 379)
Not in Bassano 1918; probably a mistake for mäzraˁti.
Mehri
ḏarˀ - arm (ML 81)
Jibbali
ḏέraˁ - arm (JL 47)
Harsusi
ḏerā - arm (HL 29)
Soqotri
diréˁi - arm (LS 136, SSL 2 212—3)