According to legend, Louise Dupin, who owned Chenonceau during the French Revolution, was responsible for dropping the "x" from the chateau's name.
Chenonceau did not always span the Cher. When Diane took possession of it in 1547, it was joined to the north shore by drawbridge. Diane dreamed of building a bridge to the south shore, which she did in 1557. The familiar three-storey structure was actually Catherine's addition. Here is a picture of Chenonceau which has been altered to suggest how Diane's bridge would have looked:
The river was a part of Diane's daily ritual when she was in residence at Chenonceau. She bathed in the cold river water daily, often joined by Henri. A trap door from Diane's bedroom allowed them to enter the water seen by the servants. They must have been brave, considering this is the view from that door!