sylv-, silv- (Latin: woods, forest).
Pennsylvania: Literally, Penn's Woods, from William Penn's name and Latin silva, "forest". The William Penn that the state was named for was not the William Penn, founder of the original colony, but after his father. In 1681, Penn was quoted, in an authorized biography, as saying: "My country was confirmed to me by the name Pennsylvania; a name the king would give it in honour of my father.... I proposed 'Sylvania' and they added 'Penn' to it."
The founder of Pennsylvania, William Penn, Jr., had a father who was Admiral Sir William Penn (1621-70), of the king's navy who was very unhappy by his son's plans for a "peaceable kingdom." Sir William was a naval hero who helped frame the first code of tactics for the British navy. He was imprisoned in the Tower in 1655 for political reasons that are still unknown. The crown, however, had become indebted to the admiral, Penn having loaned Charles II 16,000 pounds.
On June 24, 1680, the younger Penn petitioned Charles for repayment of the debt, asking for a 300-by-160-mile "tract of land in America...." This section of land was to become a colony for Protestant Quakers suffering religious persecution, and Charles repaid his debt with a charter. In the document, Charles II named the section of land, "Pennsylvania" in honor of the younger Penn's father [as stated earlier].
Father and son were reconciled before the father's death and it is an ironic footnote to history that the first settlement in the New World specifically dedicated to peace was named for a military man who was devoted to war.
(New York: Facts On File, Inc., 1997).
Morris Dictionary of Word and Phrase Origins by William and Mary Morris
(New York: Harper and Row, Publishers, Inc;1971)