I looked at this question a while back, and wrote this: https://kybernetikos.com/2007/12/03/atoms-of-english/ https://kybernetikos.com/2007/12/03/atoms-of-engli

I looked at this question a while back, and wrote this: https://kybernetikos.com/2007/12/03/atoms-of-english/ https://kybernetikos.com/2007/12/03/atoms-of-english/ (blog is only up some of the time sadly, I'll fix it eventually). I took Websters dictionary from the project Gutenberg site. I started with 95712 words. After the initial throwing away of words that weren’t in any definitions, I was down to 4489 words. After expanding them, and throwing away words that weren’t in the expanded definitions, I was down to 3601 words. Setting recursive definitions as atoms and continuing got me down to 2565 words.