Grogram is a type of fabric that's a mix of silk and wool. Grogram was once commonly used to make clothes, but it’s kind of scratchy so people don’t use it much anymore.
Combine silk with wool (or mohair) and what do you get? Grogram (if it's woven rather coarsely and/or stiffened with gum). The original French term was gros grain, for "coarse grain.” Grogram was once commonly used, but it had pretty much finished its time in the fashion spotlight by the 19th century. The more generic term grosgrain refers to similar material today. Since grogram is rough, it was good for making a jacket but not ideal for underwear.