The reason why it's called Irish stew is because of the traditional dish originated from Ireland.
Irish stew is made with readily available ingredients like root vegetables, potatoes, lamb or mutton.
Irish stew is a hearty beef stew made with garlic, stock, beef, Guinness, red wine, carrots, potatoes and onions.
The reason why you put potatoes in stew is because the potatoes help to thicken the liquid from their natural starch content.
The potatoes in stew also provides a heartier consistency to the strew and adds a great amount of earthy flavor to the stew.
Essentially the potatoes in stew acts as a thickening agent while also contributing a vegetable element to the stew.
The starch released from the potatoes as they cook in the stew helps to thicken the stew without needing to add any additional thickening agents or flour.
Stew meat for beef stew is called chuck steak although it is also known as and called braising steak or gravy beef.
Sometimes stew meat is called diced beef, stew beef or beef for stew.
The beef chuck comes from the forequarter of the cow that consists of parts of the shoulder blade, upper arm and neck.
A stew is a method of cooking where the food is barely covered with liquid and simmered slowly for a long period of time in a tightly covered pot.
Stewing not only tenderizes tough pieces of meat but the stewing also allows the flavors of the ingredients to blend.
The most common type of stew is beef stew.
However you can also use pork or chicken in the stew if you prefer.
The difference between stews and soups are that stews are thicker and chunkier.
However a very thick and chunky soup could be called a stew.
Broth is also a liquid that serves as a main ingredient for many soups, and can be considered a soup when eaten by itself.