Question: Can anybody suggest me the websites or PDFs from where I can get the meaning and etymology of Classical Arabic terms or any online dictionary of Classical Arabic language or any PDF of that dictionary?

Answer: 
There are no etymological dictionaries of Arabic, on line or in print. For a good collection of ordinary dictionaries see here: <http://ejtaal.net/>
try <http://lex.sibawayhi.org>

it's a little rough but it contains the full text of both Lane and Lisaan al-Arab, in parallel. 

It's not designed as a dictionary, i.e. something where you just look up a "word". It's a tool for exploring the lexicon. it only understands roots, and will show you all permutations for a root, so you can examine Eg all words that start with "kt" and ponder whether they share a common semantic kernel - a very old theory in Arabic lexicology. you need to read the help screen carefully and experiment. E.g. Lane and the Lisaan pick different roots for some words that have "weak" letters, and I have not yet unified them.