The word “leprechaun,” at least according to some translations, literally means “half shoe,” since leprechauns are often depicted making just one shoe. More commonly, the word's translated simply as “shoemaker.” In Irish Gaelic, the word for leprechaun is leipreachán, also written leithbrágan. Elizabethan dramatist Thomas Dekker's use of “leprechaun” in his comedy, The Honest Whore, Part 2 (1604), marked the first known appearance of the word in the English language.
To add further interest to an already fascinating fellow, to quote Fox News, “The original leprechaun was not the top-hat wearing, pipe-smoking, green clad sprite of modern day.”
Leprechauns used to wear red, at least according to the Irish writer, Samuel Lover, who wrote during the mid-1800s. Lover explained that the leprechaun wore “a red square-cut coat, richly laced with gold [and a] crooked hat, shoes and buckles” (1831). Basically, the leprechaun resembled a teeny Santa Claus.
This matches Irish poet W.B. Yeats' observation that loner fairies wear red, whereas “trooping fairies” sport green. (Yeats also described leprechauns as “sluttish, slouching, jeering, mischievous phantoms.” Doesn't exactly josh with your Lucky Charms picture, huh?)
If you want to add one of these bitty buggers to your menagerie, YourIrish.com has published an intriguing guide, suitably titled “How to Catch a Leprechan.”