no.
>> Is there a way to have Word automatically size the font larger or
>> smaller in order to fill a given cell in a table in Microsoft Word?
> no.
You can have Word space the letters to fill the cell: Table > Properties >
Cell > Options > Fit text.
Pretty ugly though (probably meant for Asian languages), and
buggy/problematic in my experience.
You get a similar effect with Ctrl+Shift+J (DistributePara).
If you want to fit the text manually, you may find the following commands
and shortcuts useful:
GrowFont Ctrl+> and ShrinkFont Ctrl+<
GrowFontOnePoint Ctrl+] and ShrinkFontOnePoint Ctrl+[
Regards.
Klaus