Did the Arabs know about Allaah before the Prophet (peace and blessings of Allaah be upon him) was sent?

 

We know that Holy Prophet's()father name was Abdullah & he had passed away before Prophet's birth.With this background please tell that what was the concept in arabs about "ALLAH"before prophet.Were they familiar to this word before prophet's birth?How did they differentiate Allah from idols,if at all they did?

You should note that Arabian societies before Islam were
not atheistic societies that denied the existence of Allaah, or societies
that were unaware that there is a Lord, Creator and Provider. They knew
that, and they still retained some traces of the religion of Ibraaheem,
and they had contact with Jews and Christians. But their problem was
that they did not worship Allaah Alone in exclusion to others; they
had other gods whom they associated in worship with Him, and which they
worshipped not on the basis that they were the Lord, the Creator the
Provider, but because they claimed that these were intermediaries who
would intercede between them and Allaah and bring them closer to Allaah.
Hence Allaah said concerning them (interpretation of the meaning):

“And
if you (O Muhammad) ask them: ‘Who has created the heavens and the earth,’
they will certainly say: ‘Allaah’” [Luqmaan
31:25]

 This indicates that they acknowledged that Allaah
is the Creator. Another aayah says (interpretation of the meaning):

“And verily, if you ask them:
‘Who created the heavens and the earth?’ Surely, they will say: ‘Allaah
(has created them)’”

[al-Zumar 39:38]  

Many aayaat indicated that they believed in the Unity of
Lordship (Tawheed al-Ruboobiyyah);
their shirk was with regard
to divinity (uloohiyyah),
as Allaah says concerning them (interpretation of the meaning):

“And
those who take Awliyaa’ (protectors, helpers, lords, gods) besides Him
(say): ‘We worship them only that they may bring us near to Allaah’”
[al-Zumar 39:3] 

i.e., they said, we only worship them so that they may
bring us closer to Allaah.