The word Hamd means to praise and the difference between praising (Hamd) and thanking is that praising can only be done with the tongue; it is not necessary that it is done for a blessing which has been granted, whereas thanking or showing gratitude can be performed by the tongue, heart, and the other limbs. The letter's Alif and Laam have been added to create the understanding of immersion and inclusion, meaning all the possible types of praise, qualifying and reverence that can exist between the heavens and the earth all belong to Allaah. Ibn Jareer writes Allaah by praising himself educated and informed the people to praise and to revere him.
Imaam Ibn Qayyim, may Allaah have mercy upon him, wrote in his book, "Tareeq al-Hijratain" every majestic attribute, every good name, every great praise, every praise and reverence, every glorification, every might and respect that could exist in their complete and eternal forms all belong to Allaah. Whatever attributes of Allaah are mentioned, whatever names he is remembered with and whatever is said in mentioning Allaah's greatness, then all are praises of Allaah and his glorification. Allaah is free from every defect and all the praises are for him and no man from the creation can enumerate his praises.
 Rabb means the master who is obeyed, the owner who has right over all things the entity who has every right to rectify the affairs of his creation. Rabb with the additional Alif and Laam is only used for the Dhaat of Allaah and Rabb is used for the creation like Rabbud Daar , the owner of the house. Allaah said in the Qur'aan,
"Return to your Lord (Allaah)" [Soorah Yoosuf: 50]
A'alameen is the plural of A'alam and it is used for everything other than Allaah. Some people think A'alam refers to mankind, jinns, angels and shayaateen but not animals and beasts. Allaah is the master and owner of everything that exists and the one who has right and authority over it. Another meaning of Rabb that has been mentioned is protector (guardian), which is related to cultivation ie Allaah the most high is the cultivator and sustainer of his creation in specific and in general.
He is the protector in general in the sense that he created all the creation, gave it sustenance, and granted it from the affairs, which benefited it in their daily lives. In specific he is the protector of his friends in that he cultivates them via Eemaan (faith), he grants them the blessing of faith and makes them good people. He removes the obstacles that may become a barrier between himself and his friends; he grants them everything good and protects them from harm. This is possibly the reason why all the supplications of the Prophets began with the word ar-Rabb, because all the meanings of their supplications fall under the specific Lordship of Allaah.
The summary of all these details is that Allaah is alone in these attributes of creating, sustenance of all the creation and in granting all the blessings. All the creation in some form or another is dependent upon him.
 Based on Tafseer al-Qur'aan al-A'dheem of Ibn Katheer, al-Jaam'e al-Ahkaam al-Qur'aan of Qurtubee, Fath ul-Qadeer of Shawkaanee, adh-Dhu al-Muneer of Ibn al-Qayyim, Fath ul-Bayaan of Nawaab Siddeeque Hasan, Mahaasin at-Tanzeel of Jamaal-ud-Deen Qaasimee and Tayseer al-Kareem ar-Rahmaan of Abdur-Rahmaan as-Sa'adee.