Inside
A housewife pillowcase is a standard size pillow case that is open on one end but with a little flap inside that you can tuck over the end of the pillow so it a) doesn't show the white of the pillow inside and b) your pillow stays put. From my experience they are much more common in Europe (but NOT the same as a European pillowcase).
pell-mell
The Pillowcase EP was created on 2006-08-22.
A jumbo pillow typically measures 20 x 28 inches. Therefore, you would need a pillowcase that is designed to fit that size, such as a standard size pillowcase.
You are sure to find a silk pillowcase at your local Walmart or BeyondBeds. If you do not live near one of those stores you can order your pillowcase online from their websites.
Get a silk pillowcase
A pillowcase is a covering that you slip over your pillow/s that matches your sheets/bed linens. It is rectantular in shape and open on one of the narrow sides to slip the pillow in/out. In the US, there are three sizes: the small size if called Standard; the medium size is called Queen; and the large size is called King.
King
in the corner of your pillowcase
a pillowcase
A European pillowcase is a square pillowcase that typically measures 26 inches by 26 inches (66 cm by 66 cm), while other pillowcases are usually rectangular and vary in size depending on the type of pillow they fit. For example, a standard pillowcase measures 21 inches by 32 inches (53 cm by 81 cm), a queen pillowcase measures 21 inches by 36 inches (53 cm by 91 cm), and a king pillowcase measures 21 inches by 42 inches (53 cm by 107 cm). A European pillowcase is also known as a Euro sham, and is often used as a decorative element in bedding arrangements. It is usually placed behind the sleeping pillows and in front of the throw pillows, creating a plush and elegant look. A European pillowcase can be made of different fabrics and have different designs, such as embroidery, buttons, or ruffles.
If the sheet is turning into a pillowcase, it would be a physical change. The sheet is not changing anything but its shape to become a pillowcase, and it most likely can be reversed to turn back into a sheet.