Dhū-l-Jalāli wa-l-Ikrām

The One who is most precious, revered and honored. The One who is the glorious and majestic lord of all generosity and bounty.

The One who is the possessor of all glory and honor. The One who is the owner of every manner of blessing, perfection, honor and majesty.

The One whose presence bestows majesty and generosity. The One who is the source of awesome splendor and abundance.
 

This beautiful Arabic phrase begins with a pronoun, followed by two attributes of Allāh.

Dhū (pronounced "thoo") = Lord of, Possessor of
l = al = the
Jalāl = Majesty, Glory
wa = and
l = al = the
Ikrām = Generosity, Bounty

The attributes of Allāh in this phrase are based on the root j-l-l meaning:

to be supremely great
to be glorious, majestic
to be sublime
to be high, lofty, far above, independent
 

and the root k-r-m which has the following classical Arabic connotations:

to be noble, high minded, generous
to be highly esteemed, honored, prized, valued
to be excellent, precious, valuable, rare
to be productive, fruitful, bountiful
 

This name is used in the Qur'ān. For example, see 55:27

Though certain benefits and gifts may arrive through human hands, one must offer all praise and honor to the True Source from which all blessings come, the One who is the Lord, Possessor and Bestower of Majesty and Bounty.

The Beautiful Names al-Jalīl and al-Karīm are also derived from these same two roots. The words jalāl (glory) and ikrām (generosity) are verbal nouns, while jalīl (glorious) and karīm (generous) are adjectives.

The demonstrative pronoun Dhū literally means with, in, on, or of, but in this phrase from the Qur'ān it is often translated as Lord of, Owner of, or Possessor of.

Note that Dhū is pronounced thoo.

When used as an invocation,  Dhū changes to Dha, as in Yā Dhal-Jalāli wal-Ikrām.