The title page of the Shakespeare First Folio, 1623. The term folio, from the Latin folium (leaf), has three interconnected but distinct meanings in the world of books and printing. It is firstly a term for a common method of arranging sheets of paper into book form, folding the sheet only once, and a term for a book made in this way.
Quick Answer. Symptoms of a burning or burn on the tongue include pain, redness and swelling, notes Healthline. More severe burns can result in blisters and even blackened skin. Those with burning tongue syndrome experience the burning pain associated with a tongue burn, but without the hot food or drink that causes it.
1 A first-degree burn involves the outermost layer of the tongue. Youâll experience pain, and your tongue may become red and swollen.  A second-degree burn is more painful because both the outermost layer and the under layer of the tongue are injured. Blisters may form, and the tongue will appear red and swollen.