Proto-MSA

*ˁamḳ- - middle (Kogan 2015: 549)

M. Bittner (1909:14, 1915b:8) and W. Leslau are undoubtedly correct to derive it from PS *ˁmḳ ‘to be deep’ (CDG 63), notwithstanding a somewhat peculiar semantic development

PS
*ˁmḳ - to be deep (CDG 63)
Semantically unambiguous cognates to this root are missing from both Akkadian and MSA. Cf. Akk. emēḳu ‘to be wise’ and MSA *ˁamḳ- ‘midst, interior’.

Mehri
ˀāmḳ - middle (ML 24)
Jibbali
ˁamḳ - middle (JL 13)
Soqotri
ˁamḳ - middle (LS 315; CSOL I 492; CSOL II 410; Naumkin et al. 2013b:545; Naumkin et al. 2015a:60)