Refugees, as defined under the 1951 Refugee Convention, are entitled to basic rights under international law, including the right not to be immediately deported and sent back into harm’s way.

“The practice of granting asylum to people fleeing persecution in foreign lands is one of the earliest hallmarks of civilization,” according to the U.N. High Commissioner for Refugees. “References to it have been found in texts written 3,500 years ago, during the blossoming of the great early empires in the Middle East such as the Hittites, Babylonians, Assyrians and ancient Egyptians.”

A refugee is someone who has been forced to flee his or her home country because of armed conflict or persecution. Syrians are a prime example.

The U.N.’s definition of refugee is someone who, “owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his nationality, and is unable to, or owing to such fear, is unwilling to avail himself of the protection of that country.”

Migrants, however, are processed under the receiving country’s immigration laws. So, ultimately, these terms have major implications for those seeking asylum and the countries being asked to grant it.

A migrant is someone who chooses to resettle to another country in search of a better life.

For example, those fleeing poverty in Nigeria, looking for work in Europe, would not have refugee status and would be considered migrants.

Migrant or Refugee? There Is a Difference, With Legal Implications (New York Times)

In the first half of this year alone, at least 137,000 men, women and children crossed the Mediterranean Sea to reach the shores of Europe, according to the United Nations. Thousands are traveling across the Balkans now.

Q. Does it matter what you call them?

A. Yes. The terms “migrant” and “refugee” are sometimes used interchangeably, but there is a crucial legal difference between the two.

Q. Who is a refugee?

A. Briefly, a refugee is person who has fled his or her country to escape war or persecution, and can prove it.

The 1951 Refugee Convention, negotiated after World War II, defines a refugee as a person who, “owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his nationality, and is unable to, or owing to such fear, is unwilling to avail himself of the protection of that country.”

Among those crossing the Mediterranean in the first half of 2015, the greatest numbers came from Syria, Afghanistan or Eritrea. Syrians are widely presumed to be refugees because of the civil war there, according to the United Nations refugee agency. Many Afghans have been able to make the case that they are fleeing conflict, the agency added, and Eritreans can generally argue that they would face political persecution at home in Eritrea, which is ruled by one of the world’s most repressive regimes.

Q. What does the distinction mean for European countries?

A. Refugees are entitled to basic protections under the 1951 convention and other international agreements. Once in Europe, refugees can apply for political asylum or another protected status, sometimes temporary. By law, refugees cannot be sent back to countries where their lives would be in danger. “One of the most fundamental principles laid down in international law is that refugees should not be expelled or returned to situations where their life and freedom would be under threat,” the refugee agency said in a statement on Thursday.

Q. Who is a migrant?

A. Anyone moving from one country to another is considered a migrant unless he or she is specifically fleeing war or persecution. Migrants may be fleeing dire poverty, or may be well-off and merely seeking better opportunities, or may be migrating to join relatives who have gone before them. There is an emerging debate about whether migrants fleeing their homes because of the effects of climate change — the desertification of the Sahel region, for example, or the sinking of coastal islands in Bangladesh — ought to be reclassified as refugees.