To me, they are synonomous, and the differences lie in the cultures of the people who recognize them.
Then how do we reconcile the very diverse ideas espoused by those supposedly synonymous beings?
It seems to me that the answer is in Lizzie's post, to which you were replying.
Within the Abrahamic religions, we have Islam, Judaism, and Christianity, with each of these three branches taking on many, many different variations, with very diverse ideas about just who God is, what God is, what his relationship is to us, and what he expects of us.
God is perfect and consistent, but Mankind is anything but. Diverse groups of men have taken what God has revealed, and filtered it according to their own perceptions, and mingled it with their own preconceived beliefs. Islam has very different ideas than Judaism, and Christianity has very different ideas than the other two. Even within Christianity, there is a wide range of diverse ideas. All traceable to the same one God, who revealed himself to Abraham. It's very much like
the old parable of the blind men and the elephant. There is only one God, and he has only one nature, and one truth, but we foolish mortals all each see only a small part of this God, and a small part of his truth, and we think we know the whole thing. And we don't even see the same parts.
As I said, I really don't know anything of any non-Abrahamic monotheistic religions, but I am sure that such must exist. The God in whom I believe would surely have reveal himself to others, in other parts of the world, not in contact with the Abrahamic faiths. And the accounts of these other cultures, filtered through and mingled with very different beliefs, might bear little recognizable similarity to the various Abraham accounts of God's dealings with these branches of Mankind..
The Blind Men and the Elephant
John Godfrey Saxe (1816-1887)
It was six men of Indostan
To learning much inclined,
Who went to see the Elephant
(Though all of them were blind),
That each by observation
Might satisfy his mind.
The First approached the Elephant,
And happening to fall
Against his broad and sturdy side,
At once began to bawl:
"God bless me! but the Elephant
Is very like a WALL!"
The Second, feeling of the tusk,
Cried, "Ho, what have we here,
So very round and smooth and sharp?
To me 'tis mighty clear
This wonder of an Elephant
Is very like a SPEAR!"
The Third approached the animal,
And happening to take
The squirming trunk within his hands,
Thus boldly up and spake:
"I see," quoth he, "the Elephant
Is very like a SNAKE!"
The Fourth reached out an eager hand,
And felt about the knee
"What most this wondrous beast is like
Is mighty plain," quoth he:
"'Tis clear enough the Elephant
Is very like a TREE!"
The Fifth, who chanced to touch the ear,
Said: "E'en the blindest man
Can tell what this resembles most;
Deny the fact who can,
This marvel of an Elephant
Is very like a FAN!"
The Sixth no sooner had begun
About the beast to grope,
Than seizing on the swinging tail
That fell within his scope,
"I see," quoth he, "the Elephant
Is very like a ROPE!"
And so these men of Indostan
Disputed loud and long,
Each in his own opinion
Exceeding stiff and strong,
Though each was partly in the right,
And all were in the wrong!
