The movement of any goods outside of the United States is considered an export.  This includes goods that you carry out of the United States in the course of international travel.

Exports valued more than $2,500 must be reported to the US government througn an EEI (Electronic Export Information, formerly known as SED, Shipper's Export Declaration) regardless of whether or not a license is required.

Exports to sanctioned countries and embargoed countries should be screened by the Office of Export Controls.  Exports to the following countries normally require a license:  Cuba, Iran, North Korea, Syria, and Sudan.

All military goods (including those produced through DARPA funding) and items qualified for operation in outer space will require a license to be exported.  While most commericial goods do not require a license to be exported, many commercial items are controlled to certain destinations.  For example, certain oscilliscopes, lasers, spectrometers, centrifuges and software packages may require a license to exported to certain countries.