Usually spelled as separate words in JBA.

For the older and later examples with different demonstrative forms, i.e., ywmˀ znh, see s.v. ywm, ywmˀ n.m.
It is noteworthy that although this form is well attested in Palestinian texts from JLA through Galilean and CPA, where it is extremely common, in PTA it is always changed to יומא הדין.