be the bee's knees

To be exceptionally great, excellent, or high-quality. Have you ever tried the pistachio gelato at this place? It's absolutely the bee's knees! I'm so crazy about the girl I've started seeing. I think she's the bee's knees, and I don't care who knows it!

dated slang Something or someone highly enjoyable, desirable, or impressive, especially in a fancy or elaborate way. Tom's new Cadillac is really the bee's knees! Boy, that singer last night was the bee's knees, wasn't she?

If something or someone is the bee's knees, they are extremely good. I loved this jacket when I bought it — I thought it was the bee's knees. Note: Some people believe that this expression refers to the way in which bees transfer pollen (= the powder that flowers make) from their bodies to pollen sacs on their back legs. However, it seems more likely that it dates from the 1920s, when other similar expressions such as `the cat's pyjamas' began to be used.

Something that's excellent. This nonsensical phrase that was popular in the 1920s was, like “the cat's whiskers,” the equivalent of today's “really cool” or “it's amazing!” It went the way of such faddish expressions, which is to say, out.