Percy m
English: originally a transferred use of a famous surname, but long established as a given name, and now often erroneously taken as a pet or informal form of PERCIVAL (SEE Percival). The surname originated as a Norman territorial name, borne by a baronial family who had held a fief in Normandy called Perci (from Late Latin Persiācum, composed of the Gallo-Roman personal name Persius and the local suffix -ācum). As a given name it was taken up in the early 18th century in the Seymour family, which had intermarried with the Percy family. The poet Percy Bysshe Shelley (1792–1822) was also distantly connected with this family, and it was partly due to his influence that the given name became more widespread. It is at present out of fashion.
First names dictionary. 2012.