Full Arabic — click to listen
wal-samāi
By the sky
P – prefixed preposition wa (oath) + DET – determiner prefix al + N – genitive feminine noun 
Root Link: س م و
dhāti
which
N – genitive feminine singular noun
Root Link: ذ و
l-rajʿi
returns
DET – determiner prefix al + N – genitive masculine noun
Root Link: ر ج ع

Acknowledgements:

Single-Word Audio has been made possible through software provided by Arabic NLP

James Ada's concordance work; his research can be found at www.organizedQuran.com
Note: James is now a member of the IslamAwakened Continuity Board