When it comes to idiomatic expressions, few terms are as delightfully confusing as "Bee's Knees." This phrase, coined in the 1920s, is a colloquialism born from the jazz scene of New Orleans. Its original meaning was quite literal: it referred to the knee joints of fashionable women, as in, "Her bee's knees are looking fine tonight, if I do say so myself."
Fast forward to today, and the phrase "Bee's Knees" is more often associated with the phrase "The bee's knees," which means something is "the cat's pajamas," or excellent. This usage is often employed to describe the best thing since sliced bread or, in the case of our beloved example, a perfectly good cup of coffee.
For more on idiomatic expressions, check out our sister page, "It's Raining, It's Pouring," or our other idiomatic expressions.
*This article was brought to you by the Bee's Knees Institute of Etymology, a non-profit organization dedicated to the preservation and study of obscure phrases.