In the Bible, Israel refers to a person, a people, a nation, and a place.
The person Israel (originally called Jacob, Genesis 32:28) was Abraham’s grandson (Isaac’s son) .
Jacob/Israel had twelve sons, which eventually became the twelve tribes of Israel (Matthew 19:28), the people of Israel, and later the nation of Israel. In the Bible, they were called the Israelites; nowadays, they are called Israelis.
The land in which they eventually settled was also called Israel.