Which word contains more letters than any word in English language?

The Word "smiles" contains a "mile" in the middle, but it's not the longest Word in the English language. The longest Words are often technical or coined terms, such as "pneumonoultramicroscopicsilicovolcanoconiOSis," which refers to a lung disease. However, there is no single Word that is universally recognized as containing more letters than any other in the English language, as new Words can be created or technical terms can be extremely lengthy.