An export is a shipment or transmission of items out of the United States. A common understanding is that exports refer to items physically shipped out of the country. However, there are many other ways in which something can be exported, such as: auditorily, visually, verbally, or electronically.
Per the Department of Commerce, exports also include any release of technology or source code subject to the EAR to a foreign national, whether in a foreign country or in the U.S. Such a release is "deemed" to be an export to the home country or countries of the foreign national. Technology or software is "released" for export through visual inspection (such as reading technical specifications, plans, blueprints, etc.), oral exchanges, or electronically. It also includes the application to situations abroad of personal knowledge or technical experience acquired in the United States. The justification for the deemed export rule is that working in a laboratory is an effective way to access sensitive technical information.
The deemed export rule is an area of particular concern to institutions of higher education. A deemed export license may need to be obtained before releasing controlled technology or software to a foreign national. Note that persons with U.S. citizenship, permanent resident status (Green Card holders), and persons granted status as "protected individuals" are exempt from the deemed export rule.
The Department of State's definition of export does not use the words "deemed export" but includes "disclosing (including oral or visual disclosure) or transferring technical data to a foreign person, whether in the United States or abroad."