‘Grand’ may recall a planned square, or simply the street’s breadth.
Grand Street crosses lower Manhattan from Varick Street to the FDR Drive, on land once owned by James De Lancey Jr. One account says it was laid out as a grand boulevard leading to a planned Delancey Square; Forgotten New York thinks the name more likely refers to its width, considerable for the 19th century. The street was probably developed in sections in the early 1800s.