Seal of the United States Department of Commerce.
The seal was approved on April 4, 1913 and is derived from the seal of the defunct United States Department of Commerce and Labor. It is composed of the arms (Per fesse azure and or, a ship in full sail on waves of the sea, in chief proper; and in base a lighthouse illumined proper), and crest ("The American Eagle displayed"). Around the arms, between two concentric circles, are the words "Department of Commerce" and  "United States of America".
The official symbolism has been modified as the functions of the department have changed.  As of 2007: the ship is a symbol of commerce; the blue denotes uprightness and constancy; the lighthouse is a well-known symbol representing guidance from the darkness which is translated to commercial enlightenment; and the gold denotes purity. The crest is the American bald eagle denoting the national scope of the Department's activities.

Full description at CFR Title 15 Part 1
Sceau du fr:Département du Commerce des États-Unis
United States Department of Commerce.