Webster's Dictionary refers to the line of dictionaries first developed by Noah Webster

Noah Webster

Noah Webster was an American educator, lexicographer, textbook pioneer, English spelling reformer, political writer, editor, and prolific author...

 in the early 19th century, and also to numerous unrelated dictionaries that added Webster's name just to share his prestige. The term is a genericized trademark

Genericized trademark

A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...

 in the U.S.A. for comprehensive dictionaries of the English language.
Noah Webster

Noah Webster

Noah Webster was an American educator, lexicographer, textbook pioneer, English spelling reformer, political writer, editor, and prolific author...

 (1758–1843), the author of the readers and spelling books that dominated the American market at the time, spent decades of research in compiling his dictionaries.