This is a common word you will see around Japan, especially if you are waiting to buy concert tickets or to get a seat at a restaurant.
最後尾 (さいこうび) - End of the line
Some lines in Japan can get very long, and to maintain a civil process of no cuts, a person working the event will stand at the end of the line with this sign. This makes sure that everyone knows - this is the end, stand here.
Sometimes they may also have a wait time estimate, but we all know those are bullshit. Save yourself and your workers a headache and forget the estimate. Just say, 最後尾.
And be careful of the hobbyist. This is a true story, an adult student at an English School I worked at when I worked in Japan told us once, their hobby was standing in lines. If they saw a line, they would stand in it and see where it would lead. Often times, it was to the opening of a restaurant or food stand. You need a lot of time to have this hobby.
When I was there, they also opened a Krispy Kreme donuts. The line was very long. It went around the corner and even cut across the street. They needed three workers to manage the line. One at the end of the line on one side of the street, one at the beginning of the line on the other side of the street and one at the end of the entire line on that side of the street as well.
I hope it was worth it.
終です。
ジョシュア