Linotype was a machine — and the system around it — used in newspaper and book printing from the late 1800s well into the twentieth century. The operator typed on a keyboard, and the machine cast a whole line of words as one solid strip of metal, ready to print. That was much faster than picking letters one by one. Type here means the metal letters used in printing, not “a kind of thing”. The name began as a trademark and then became a general word: line plus type. You meet it in the history of newspapers, in museums, and in old print shops. Nobody sets a daily paper this way now; computers replaced it. A capital L is common because it started as a brand, but you also see it treated as an ordinary noun.