You’re familiar with these lucky customs. Here’s where they come from:
LUCKY STAR. Centuries ago, people believed that every time a person was born, a new star appeared in the sky. The star was tied to the person’s life: it would stay in the sky until the person died, and it rose or fell as the individual’s fortunes rose and fell (that’s where the expression “rising star” comes from). The Hebrew phrase mazel tov, which means “good luck,” also translates as “good constellation,” or “may the stars be good to you.”
LUCKY CHARM. “Charm” comes from the Latin word carmen, which means “song” or “incantation.” People once believed that certain words or phrases had magical powers when recited – some-thing which survives today in words like “abracadabra” and “open seasame.” In time, anything that brought luck, not just “magic words,” became known as charms.
STARTING OUT ON THE RIGHT FOOT. A term from the ancient Romans, who believed that entering a building with the left foot was bad luck. They took the belief to extremes, even stationing guards of “footmen” at the entrances of buildings to make sure every visitor “started out on the right foot.”
THIRD TIME’S A CHARM. Philip Waterman writes in The Story of Superstition, “Of all the numbers in the infinite scale, none has been more universally revered than three.” The Greek philosopher Pythagoras thought the number three was the “perfect number,” and many cultures have used triangles to ward off evil spirits. The reason it’s bad luck to walk under a ladder (aside from the obvious ones) is that you’re “breaking” the triangle that the ladder makes with the ground.
“Taken from Uncle John’s Biggest Ever Bathroom Reader“