When you're lucky, things work out well for you — you experience good fortune. If you're feeling lucky, it might be a good day to buy a lottery ticket or guess the number of jelly beans in a jar.
Lucky people seem to have everything going for them, and your lucky charm (like a rabbit's foot or a four-leaf clover) seems to bring that kind of success in your direction. Some lucky things are happy coincidences: "How lucky that I ran into you this morning!" When you're envious of someone else's big break, you can say, "You lucky devil." Lucky and luck come from the Middle Dutch gheluc, "good fortune."