As is typical for a literalist, Clanad misleads you, because this kind of discussion makes it abundantly clear their book is plain wrong. There most certainly was a word for sphere in ancient Hebrew, namely 'kadur'.
The notion that circle means sphere is not supported by lexicographical evidence (or indeed common sense), though it does make sense when you consider the Creationalist's difficulties in the face of the Bible being obvoiusly erroneous. Enter the usual tricks of the literalist: "Oh yes, well, obviously *that* bit isn't meant to be interepretted literally"...
(Perhaps one day the literalists will be good enough to make available to all their closely-guarded source that tells them *when* to interpret things literally or as a metaphor etc)
The Bible says many things about cosmology, but let's stick with the sphere for a moment.
Daniel 4:7-8 talks about a tree at the centre of the world. Not possible on a sphere.
Isiah 42:5; 44:24 uses a Hebrew word 'flatten out' to describe God's action in creating the land. Again, not consistent with a spherical Earth, (but consistant with a human living in a generally flat desert region)
Jesus believed the stars were little lights mounted on the inside of a canopy (imagine the Earth and the stars as being like a snowstorm, and you have the idea). You'd have thought He'd have known better, wouldn't you?
Satan takes Jesus up onto a high mountain so Jesus can view all of the kingdoms of the world. Somewhat difficult on a sphere, so we must conclude either that we are talking about a God that only ruled over a small region or that they believed the world was flat.
There are many other examples of the Bible talking rubbish about cosmology, not least of which is the amusing God creating light on day 1 of creation, then stars & the actual bodies that create light on day 4 in Gen 1 (but presumably there is