The Quran is one of the earliest full texts that we have in Arabic. It probably existed in some written form by the time Muhammad died in 632 and it was taken down in its current form (with the exception of diacritics and other hotly debated issues not particularly relevant to this discussion) during the reign of the Caliph Uthman (r. 644-656) (which is why the standard, surviving form of the Quran is known as the Uthmanic Codex).

Based on its age and the relatively small body of pre-Islamic texts that have survived, the Quran is therefore the earliest attributed source for a huge number of words in Arabic.

Given the utter primacy of the Quran in Islam there's been a huge amount of effort, particularly in Arabic, to trace the etymologies and define the meaning of every word in the Quran.

Nonetheless, it's impossible to say for sure whether Quran "introduced" these words to the language or whether they were in common usage and are simply recorded in the Quran for the first time. In English there's a similar problem in defining the number of words "introduced" by Chaucer, for example.

The Quran also contains a number of words and phrases for which we have no definite understanding of their meaning. The "Mystical Letters" that start some Suras are one example where if they had a known meaning that meaning has since been lost. Again we run into a similar problem however where it's impossible to tell with these strange words whether they were introduced by the Quran or whether the Quran is simply their only remaining record and we've lost the meaning of them.

The catchall term for these sorts of words is a "hapax legomenon" (usually just hapax, pl. hapaxes).

Here's a good article that includes a detailed explanation and list of all such words broken down by type and with an overview on the relevant academic literature: http://shawkutis.weebly.com/uploads/1/9/7/4/19747661/hapaxes.pdf

This website http://corpus.quran.com/ is invaluable and is run by the University of Leeds and includes word by word analysis of the quran. You can view a list of every verb in the quran sorted by frequency on their page here: http://corpus.quran.com/verbs.jsp

edit: The best introduction to the Qur'an's vocabulary, structure, format, composition, etc. that I'm familiar with is Neal Robinson's Discovering the Quran. Unfortunately there is no Quranic equivalent of something like the Oxford Annotated Bible that includes critical scholarship. The best you can do is take a good English translation (I like Pickthall) and match it with both the religious tafsir as well as critical academic scholarship.