The word mongoloid was introduced by 18th century ethnologists to describe Central Asian and East Asian part of a three part division of race: Mongoloid, Caucasoid, and Negroid. Some forensic anthropologists continue to use the word in criminal cases but their usage is now discouraged by most anthropologists due to the questionable nature of such models.
In addition, Mongoloid had a second usage, now generally avoided as highly offensive. Until the late 20th century, people with Down syndrome were often referred to as "Mongoloids" or in terms of "Mongolian idiocy" or "Mongolian imbecility". Down syndrome has nothing to do with Mongolid people: it is a genetic condition found in all types of humans.
Mongoloid (race) Facts for Kids. Kiddle Encyclopedia.