Allah says in the holy quran in surah Al A'raf :
"And the most beautiful names belong to Allah alone. So call on him by them"
WE MUST ALL THEREFORE BEAUTIFY OUR DUAAS BY CALLING ALLAH WITH HIS BEAUTIFUL NAMES. .
"DHUL JALAALI WAL IKRAAM " IS ONE OF THE 99 NAMES OF ALLAH SUBHAANAHU WA TA'AALA.
THIS NAME IS ALSO MENTIONED IN THE HOLY QUR'AN.
AND WHEN WE MAKE DUAA , "DHU" CHANGES TO "DHA" AS IN "YAA DHAL JALAALI WAL IKRAAM"
MEANING OF "YAA DHAL JALAALI WAL IKRAAM" :
"O OWNER OF MAJESTY AND HONOUR"
It refers to
The one who is Most Precious, and Honoured.
The one who is posessor of all Glory and Honour.
The one who bestows majesty and GENEROSITY.
The one who is the owner of PERFECTION.
The one who is SUPREMELY GREAT.