A Lemon Drop is a small, hard, lemon-flavoured boiled sweet, a type of Muggle confectionery. They are typically yellow and translucent. In the original British editions of the novels, this sweet is referred to by its common UK name, the sherbet lemon, which is a hard lemon-flavoured shell with a fizzy sherbet powder centre.
Lemon Drops possess no inherent magical properties. Their significance in the wizarding world is derived entirely from their use by Albus Dumbledore.
The first mention of Lemon Drops (as sherbet lemons) occurs in the opening chapter of the first book. After delivering the infant Harry Potter to Privet Drive, Albus Dumbledore offers a Lemon Drop to a visibly stressed Minerva McGonagall, who declines. In Harry Potter and the Chamber of Secrets, Harry Potter learns that “Lemon Drop” is the password to the Headmaster's office. He uses it to gain entry and speak with Dumbledore for the first time in his study. Dumbledore was known to change his password periodically, always using the name of a different sweet, such as Cockroach Cluster or Fizzing Whizbee.
Though a simple object, the Lemon Drop plays a subtle but important role in the series.
A notable difference exists between the original British publications and the American editions of the books. In the UK editions, the sweet is consistently called a “sherbet lemon.” The American editions changed this to “lemon drop,” a more commonly understood term for a hard lemon candy in the United States.