Scrabble dictionary doesn't match Webster's!

I always assumed that Websters would have MORE words than the Scrabble Dictionary, not less.

I assumed it would have every word in the Scrabble dictionary, plus all the capitalized words, etc.

But it seems not so.

The last word in the Scrabble Dictiobary is ZZZ, followed by ZYZZYVA, followed by ZYMURGY followed by ZYMOSIS.

None of them are in Websters.

Websters starts with zymosan - something to do with yeast. (The suffix "zymo" is Latin for  leavening.)

Now, in the past, I have come across some words in the Scrabble Dictionary that are not in the Dictionary.com online Dictionary, and you have to search the web long and hard to find them, but ZYZZYVA, ZYMURGY and ZYMOSIS are all in there.

So I'm very surprised they're not in Websters!

ZYZZYVA is a weevil, by the way, not to be confused iwht ZYZZPHA, which is a whelk (and which is neither in the Dictionary.com online versin, or in Websters, but is in WIkipedia.