(Wahid). Unique and one. The words wahid and ahad both mean 'one and unique'. Ahad may apply to Allah and also to what is other-than-Allah, but wahid applies only to Allah Himself. No one else is named or described by the word wahid.
(Dhat). The Essence. This is Allah in Himself without regard to His creations, His Attributes or His Names. The Essence is beyond knowledge or conceptualization. Allah warns us of this aspect of Himself. The Essence is Absolute Blindness, the Hidden of the Hidden, the Unknown of the Unknown. This is the World of Absolute Non-manifestation.
Essence
(Ghayr Allah). 'Other than Allah' is the cosmos and all that it contains. To be 'other than Allah' is to be imperfect, but this 'imperfection' is in itself Perfection!
Other than Allah