Where did the word lobbyist come from?

“President Grant was not a big fan of the White House, and he liked to get out and have a cigar in the evening,” Fawcett says. “He would go to the lobby of the Willard Hotel almost every night for a cigar and drink. People would wait in the lobby until he got there and then talk to him informally about what it was they needed. They became known as lobbyists.”