The meaning ‘swallow’ is conjectural since the word is attested only as a divine designation in 1.17 II 27 and parallel passages: ˁrb bbth kṯrt // bnt hll snnt kṯrt ‘entered his house // daughters of the light, swallows’
PS
*sVnūn(Vw)-at- - swallow
(SED II No. 197; Kogan 2011: 210)