How you you define the word: believe?

Someone commented on an answer I left (in which I wrote about withholding belief until a claim is proven true) and wrote this in response: "The very word believe means to accept as true something which cannot be proved."

That seems to me to be wrong and absurdly narrow. I wouldn't even define "faith" that narrowly. I define faith as belief without evidence, but not necessarily about something that is unprovable.

But that got me thinking, is the word 'believe' only applicable to accepting as true some proposition which simply has not been proven (although could be)?

So I looked up "believe" in the Shorter Oxford English Dictionary and found this definition: "accept the truth or reality of (a proposition, etc.)." That seems right to me as it seems to leave open the point at which (i.e. the level of evidence shown) you choose to accept the truth of the proposition.

Then there is also the person tonight asking atheists about what invisable (sic) things atheists believed existed and when I answered the 2nd time I started to wonder what that poster's definition of "believe" was. Does that poster think believing is only applicable to something unproven to exist? Hence this question to everyone.

So, do you think believing has anything to do with the thing at issue (the proposition) being unprovable?

Do you think believing has anything to do with evidence tending to prove the proposition true?

If someone has some proposition and provides enough supporting evidence to prove that proposition true beyond any doubt, is acceptance of that proposition as true "belief" or is some other word more appropriate? In other words, does use of the word 'believe' carry the connotation that there is insufficient evidence to prove the proposition?