High street bookshop Waterstone's has announced it is dropping the apostrophe from its name to make it more "versatile" for online use.
Managing director James Daunt said the amendment was a "more versatile and practical" spelling of the name for the digital world.
But chairman of the Apostrophe Society John Richards has condemned the change, calling it "just plain wrong".
He told the Telegraph newspaper it was "grammatically incorrect".
The book shop has also reinstated the Baskerville serif font with a capital W, which Mr Daunt said "reflects authority and confidence".
He added: "It also reflects an altogether truer picture of our business today which, while created by one, is now built on the continued contribution of thousands of individual booksellers."
Some customers have criticised the move on Twitter.
Alex Deane said: "Waterstone's, don't drop the apostrophe. McDonald's & Sainsbury's manage! You claim to play an educational role, not lead in dumbing down!"
David Skelton called the decision "a load of nonsense".
The new design will gradually be rolled across all correspondence and high street stores.