Western Asia is the southwestern part of the Asian continent. Unlike the Middle East, which includes African countries, West Asia is a geographical term that includes the southwestern end of the continent of Asia, and is used to describe this region in historical studies.
Southwest Asia lies on some border with the Middle East and the Near East, which describe their geographical position in relation to the continent of Europe. The term West Asia has become the preferred term for use for the Middle East by international organizations (such as the United Nations) as well as for African and Asian countries. Geographically, culturally and politically, the Middle East includes North African countries such as Egypt and Sudan.
The UN also includes Armenia, Azerbaijan, and Georgia in the secondary West Asian region, because they are located almost entirely in that region. But in any case, these countries are also located in the Caucasus, the region that straddles both Asia and Europe, and they have social and political ties with them. The Asian part of the Arab world (which includes the Arabian Peninsula) is called the Arab Mashreq.
In Arab history, the name Southwest Asia was not mentioned, nor did the Middle East, as they are purely modern geographical or political names.
The term is used pragmatically and has no "correct" or generally agreed upon definition. Their typical definitions overlap largely, but not completely, with those of the Middle East, Eastern Mediterranean, and Near East (which is historically familiar but widely neglected today). National Geographic Patterns Handbook as well as Madison's Global Economy: Historic Statistics (2003) by the Organization for Economic Co-operation and Development (OECD) includes only Bahrain, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Palestine (later called the West Bank and Gaza), Saudi Arabia, Syria, Turkey, UAE, and Yemen As countries of West Asia. In contrast to this definition, the United Nations Industrial Development Organization (UNIDO) in its 2015 yearbook also includes Armenia and Azerbaijan, and excludes Israel (as other countries) and Turkey (as Europe). Unlike the United Nations Industrial Development Organization (UNIDO), the United Nations Statistics Division (UNSD) excludes Iran from West Asia and includes Turkey, Georgia and Cyprus in the region. In the United Nations' Eastern European Geopolitical Group, Armenia and Georgia are included in Eastern Europe, while Cyprus and Eastern Turkey are located in Southern Europe. These three countries are included in the European category of the United Nations Organization