Mock Orange, English Dogwood (Philadelphus coronarius).
Mock Oranges are shrubs, hardy to USDA zone 4. Flowers are large, terminal or axillary, corymbose, racemose or solitary, white or cream-colored. About 50 species, natives of North America, Mexico, Asia and central Europe. Most plants grow in the southern and western parts of North America. They are called Mock Orange from the orange-like blossoms of the various species.
If you want more information about this flower, just search the plant's Latin name on Google: