Trade is the transfer of ownership of goods and services from one person or entity to another. Trade is sometimes loosely called commerce. Trade is used widely by the more primitive populations in the Pegasus and Milky Way Galaxies. The Atlantis expedition also trades food, medical supplies and sometimes even weapons with other societies in the Pegasus Galaxy. If there is the opportunity to trade technology then the Atlantis Expedition will trade more valuable information with them. The Tau'ri on Earth also trade technology.