How many words have four vowels?

There's no easy way to calculate the exact number of words with four vowels in the English language. Here's why:

* Dictionaries vary: Different dictionaries have different word lists. Some might include technical terms, slang, or proper nouns.

* Vowel combinations: The definition of a "vowel" can be flexible. Do we count "y" as a vowel when it sounds like one?

* Word length: There's no restriction on word length. Do we include words like "abbreviations" or "pneumonoultramicroscopicsilicovolcanoconiosis"?

To find some words with four vowels, you could:

* Use a dictionary: Look for words with at least four vowels.

* Try searching online: Look for word lists specifically focused on vowel combinations.

Remember, even a thorough search won't give you a definitive answer, as new words are constantly created and the definition of a "word" itself is open to interpretation.