According to Merriam-Webster, the meaning of a Concentration Camp is "a camp where persons (as prisoners of war, political prisoners, or refugees) are detained or confined." Unfortunately the usage of these camps are without trails for people's so-called crimes. Use of the word concentration comes from the idea of concentrating a group of people who are in some way undesirable in one place, where they can be watched by those who incarcerated them. For example, in a time of insurgency, potential supporters of the insurgents may be placed where they cannot provide supplies or information.
The earliest of these camps may have been those set up in the United States for Cherokee and other Native Americans in the 1830s; however, the term originated in the reconcentrados (reconcentration camps) set up by the Spanish military in Cuba during the Ten Years' War (1868–1878) and by the United States during the Philippine–American War (1899–1902). Polish historian Władysław Konopczyński has suggested the first concentration camps were created in Poland in the 18th century, during the Bar Confederation rebellion, when the Russian Empire established three concentration camps for Polish rebel captives awaiting deportation to Siberia. The English term "concentration camp" grew in prominence during the Second Boer War (1899–1902), when they were operated by the British in South Africa. There were a total of 45 tented camps built for Boer internees and 64 for black Africans. Of the 28,000 Boer men captured as prisoners of war, 25,630 were sent overseas. The vast majority of Boers remaining in the local camps were women and children. Over 26,000 women and children were to perish in these concentration camps.
In the 20th century the arbitrary internment of civilians by the state became more common and reached a climax with Nazi concentration camps (1933–1945). As a result of this trend, the term "concentration camp" carries many of the connotations of "extermination camp" and is sometimes used synonymously. A concentration camp, however, is not necessarily a death-camp. Because of these negative connotations, the term "concentration camp", originally itself a euphemism, has been replaced by newer euphemisms such as internment camp, resettlement camp, detention facility, etc., regardless of the actual circumstances of the camp, which can vary a great deal.
So, where does that leave the understanding of the Japanese-American during WWII? “We knew we had been in concentration camps. Even President Roosevelt used the term. But by the wars end the word concentration camp had taken on a meaning of unimaginable horror. So one of the reasons we didn’t talk much about them is not that they were so bad, but they weren’t bad enough.” Quoted by documentary A Rabbit in the Moon, by Emiko Omori.Let us not misinterpreter what these "detention centers" really represented and learn from our past's mistakes.