What does “Said to Contain” (STC) mean on a bill of lading?

Said to contain means that the shipper that has loaded the goods into the container has done his best to make sure that the goods which are loaded into the container are matching the description of goods stated on the bill of lading in a containerized shipment. 

Because of the fact that carriers could not know exactly what would have been loaded into the containers, they add this expression on the face of the bills of lading that they have issued in order to protect themselves.

A carrier or a forwarder has no knowledge of the contents of the container unless the container is stuffed by the carrier, forwarder or their agents. 

The shipper that has loaded the goods into the container should take necessary steps to ascertain the contents of the container.

"Said to Contain" or “STC” generally added to the description of the goods on the bill of lading. 

This term means that the content of a sealed container received by the carrier as is without any additions.