Kilroy is not a famous man you are expected to know, and he is not a real person you will meet. He is a name people write, most often in the sentence “Kilroy was here.” During the Second World War, US soldiers wrote that on walls, ships, and other places they had passed through — as if a mysterious Kilroy had already been there before them. The drawing that often goes with it is a bald head and a long nose peeking over a wall. Why they chose that joke is not known for certain. One story people tell is that a real American inspector named Kilroy wrote it on ships after he had checked them; another is that soldiers simply liked the name. Treat those as stories, not as a tidy fact. The surname itself comes from Irish. Today “Kilroy was here” is still a bit of writing on a wall, or a joke meaning “someone was in this place before you.”

基爾羅伊（「Kilroy was here」裡那個虛構的人；台灣多半直接留英文，意思接近「到此一遊」）