What are the differences between carriers and freight forwarders?

Definition of Carrier in International Conventions:

Global sea cargo transportation is governed by international conventions.

The first convention signed in international scale related to international sea transportation is known as "Hague Rules".

The full name of this convention is "International Convention for the Unification of Certain Rules of Law relating to Bills of Lading and Protocol of Signature".

Hague Rules drafted in Brussels on 25 August 1924 and defines the carrier as follows:

"Carrier" includes the owner or the charterer who enters into a contract of carriage with a shipper.