AL-HAMD Lexicography
‘Al’: Arabic definite article, joined in writing to the following word, and in pronunciation (Wasla-t) to the previous one. (Arabic English Dictionary, F. Steingass).

In Arabic “Al” is used for specific, all, all that, earlier. (Dars-e Quran, Dars-e Quran Board). Also see "Al" in Lughat-ul Quran, Muhammad Abdur-Rashid Nomani.

Hamd : Praise, Kindness, Favour, Grace, Reward, Thank. (F.Steingass)
Hamdun: Eulogy , Commendation. (Wortabet)

“Hamd is not only praise but it also implies admiration , and it implies the magnifying or honouring , of the object thereof , and lowliness, humility or submissiveness in the person who offers it”.
(Vol-I, Tafsir-ul-Quran, A.M. Daryabadi)

Al-Hamd : Ever all the Praises – present, past and future – are due to God Alone, because He is the Creator of all things and He is the Bestower of all Blessings, whether direct or indirect. Similarly the original source of all bounties and blessings is Allah Alone, though these may be delivered through any mode, medium or vehicle. Shabbir Ahmed Usmani says that the translation as “ `All kinds of praises’ is not a correct translation, because there is no limit of God’s praises” (Tafseer-e-Usmani).

For more details of meaning and comparisons with synonyms for the word "Hamd", also see:

i. Pages 1013 – 1020, `Ta’leemul Quran’- Mushtaq Ahmed Khan.
ii. 'Lughatul Quran' – Muhammad Abdur-Rashid Nomani.
iii. Mutaradifatul Quran’ – Abdur-Rahman Kailani (pp. 347)
According to Kitabu’l Tarifaat’ “Praise” (Hamd) of God is of three kinds:
i. Al-Hamdu’l Qauli: The Praise of God with the tongue, with those attributes with which He has made known Himself.
ii. Al-Hamdu’l Fi’li: The Praise of God with the body (liturgical) according to the Will of God .
iii. Al-Hamdu’l Haali: The Praise of God with heart and spirit.
(A Dictionary of Islam, Thomas Patrick Hughes)