The use-mention distinction is the distinction between ''foo'' and ''"foo"''.
When I say "His name is Bill" I am ''mentioning'', not using, the name "Bill",
despite the absence of quotation marks. When I say "Bill, can I talk to you
for a minute?", I am ''using'' the name "Bill".

"Playing with the use-mention distinction" isn't "everything in life, you know". -- DouglasHofstadter