Meaning of "de" in 16th century names

[Latchfordian]

Having taken my research back to the 16th century I am coming across names such as "Thomas de Webster Naylor". What exactly is the significance of that "de"? His children are also Naylor so that's obviously the father's name so could Webster be the mother's maiden name?

[Vance Mead]

"de Webster" doesn't really make sense in this context, though "le Webster" does. "de" should refer to a place, like de Vere or de Neville. In medieval records someone might be identified as William Jones le weaver. The records in the 15th and early 16th centuries were usually in Latin. Classical Latin didn't have the definite article le but in late Medieval Latin in England it was used, borrowed from French.

[Andy J2022]

It comes from the Latin, (via medieval French) meaning 'off, from'. So in the context of a name, it denotes the connection to a wider family.  Over time it became what is known as a nobiliary particle, usually denoting a territorial link to a region. (see Wikipedia on the subject of French nobility). By the 16th century in England such links were pretty tenuous, and the regional connection was probably long gone. Nevertheless its use in a name like de Webster Naylor signifies a wider family group where the Webster and Naylor families have become joined, usually by marriage. So you may be right that Webster comes from a maternal line but the actual union may have been many generations earlier. Webster as a surname is not a toponym; it is an alternative to the word weaver, and has a Germanic root from the word weber. Naylor came from the occupation of nail maker, with the word nail itself deriving from the Germanic nęgel.

[Latchfordian]

Thank you Andy J2022 for that detailed and informative answer to my query. You've enabled me to move a little further up my genealogical learning curve!