Wilcox (sometimes spelled Willcox or occasionally Wilcocks) is one of a number of English names based on a combination of a given or Christian name (in this case, William) and the ending cox (rooster.) The ending probably began as a friendly nickname and resulted in names such as Alcock (derived from Alfred or Albert.) and Hancock (derived from Hankin, a medieval form of John.)
William itself is an Old French (Germanic) name derived from the the Germanic words wil, meaning "Wish, or desire" - the origin of the modern word will - and helm, meaning "protection" (literally, "helmet.") Although now a well known English name, it was unknown in England before it was brought from Normandy in the Conquest of 1066 - as the name of the new King, it quickly became very widespread in 11th century England, and has been a royal name ever since - Prince William will be the 5th king of that name.
William itself is an Old French (Germanic) name derived from the the Germanic words wil, meaning "Wish, or desire" - the origin of the modern word will - and helm, meaning "protection" (literally, "helmet.") Although now a well known English name, it was unknown in England before it was brought from Normandy in the Conquest of 1066 - as the name of the new King, it quickly became very widespread in 11th century England, and has been a royal name ever since - Prince William will be the 5th king of that name.