adi - up to, as far as; until, up to (connoting time); concerning, as to
(CAD A₁ 115, AHw. 12)
Also adu, gadu, ḳаdu, ḫadu, ad. The background of variants with initial ḳ and g is difficult to establish.
GAG § 114 j analyzes adīni and adīšu as lexicalized combinations of adi and pronominal suffixes.
It is not obvious that forms of the type (wV)d meaning “to, towards” are related to this preposition (Arakelova 2001:22). They are united into a separate lexeme, see *ˀVd/d.