Back in the 20s, knees seem to have been very important to flappers. Showing one’s knees, if you were a woman, was very provocative.
Bee’s knees is said to be a reference to Bee Jackson, the first white girl to feature the Charleston, the dance most often associated with the 20’s and flappers. Jackson put on the dance on Broadway when she appeared in “The Silver Slipper” in February of 1924 after having seen it performed in the colored (the term used at the time for African Americans) musical show “Runnin’ Wild” that was the rage of Broadway.
She went on to introduce the dance at the Club Richmond and the El Fey Club. And in 1925, Jackson went on to play the role of “danseuse” Betty Lee in the movie “Lying Wives.” But more importantly, Bee Jackson was crowned the world Charleston champion and her legs were insured for $10,000 US ($1 in 1920 terms is equal to $10.23 in 2009 terms) — a princely sum at the time.
But the term was in print before Bee Jackson and so this explanation is flawed. The first printed reference to it I can find is in the Ohio newspaper The Newark Advocate, April 1922, under the heading ‘What Does It Mean?‘ where the journalist wrote:
“That’s what you wonder when you hear a flapper chatter in typical flapper language. ‘Apple Knocker,’ for instance. And ‘Bees Knees.’ That’s flapper talk. This lingo will be explained in the woman’s page under the head of Flapper Dictionary.”
Some will tell you the reference has to do with the similarity between bees carry pollen back to the hive in sacks on their legs (a sweet treat) and the sight of a young woman’s previously hidden asset (a sweet treat for any young man to see at the time). Still others will tell you it’s a corruption of the word business.
What we do know is that if something is said to be the “bees knees” it means that it’s something worthy of attracting other people’s attention. For that reason, I’d be inclined to go with the pollen-carrying bee theory for the phrase.