I tried to post a book and received a warning that the book listing is for a 16-point font and if it isn't I can't list it under the ISBN... how can I tell???  I checked the title and info/publisher pages, and it mentions "Revival" font but does not state the size.  Seems large to me, but I don't want to cause a problem or have it challenged, y'know?

Large Print is defined as print that is at least 16 points in size.

If you send me the ISBN I can verify it for you.  There's more than one site that will let you know if it's a large print or not.  An easy one is to put the ISBN in an Amazon search and they'll indicate if it's large print within the title.

If it's a HarperLuxe book it's a Larger Print - a bit smaller type than the 16 point (I think it's 14 point but won't swear) 

Does the book say Large Print on it? Then it probably is 16 point, I don't think they can print Large Print on the book if it isn't at least 16 point.  If it says Larger or doesn't say Large Print on it, then it probably isn't 16 point.

Another factoid I didn't know until right now 

It's a Scholastic children's book in a hardcover edition.  It honestly looks like about 14 pt font to me, but I'm not familiar with this particular font.  There is not note about it being large print (or any print size) on the book anywhere.  The ISBN I entered recognized the correct title and that it was hardcover, but then I got that big warning message that I would be in the doghouse if I dared post it under the (correct) isbn and have it not be 16-pt.... ??????  It gave me options to repost as something else, or I could just list it as a no-isbn book, but I've never had this happen before and I'm just curious if there is some magical way to tell LOL.  The isbn is 0-439-85088-6 if anyone wants to see if they get the same weird message I did! 

I have about 20 large print books by several different publishers. They all state Large Print or Large Print Edition on the publication page (back-side of title page) but I don't know that all LP publications do that.  None of them my books are Scholastic, however...

eta: The industry standard for large print is 16 point type or larger.  Also, the ISBN you've given does show  Large Print on the Book Details page, so even if it came to us with incorrect data, you do not want to post your book there until it is corrected.  You can always post it as 'a book without an ISBN' and add the true ISBN to the bottom of the description field.