* No definitive list: There's no single, official dictionary that contains every single word in the English language.
* Constantly evolving language: New words are coined and older ones fall out of use all the time.
* Different word forms: Do you want to count words like "themselves" or "something"? This would impact the total.
* Technical and specialized terms: Should we include words that are primarily used in specific fields?
However, you can find a good estimate:
* Use a word search tool: Many online dictionaries allow you to search for words containing specific letters. Try a few different search engines and see what results you get.
* Look at word lists: Resources like Merriam-Webster's or Oxford English Dictionary might provide larger lists of common words that you could use to search for "them" yourself.
Remember, any result you find will be an approximation, but it should give you a good idea of how common "them" is in the English language.