Lei is a Hawaiian word for a garland or wreath. More loosely defined, a lei is any series of objects strung together with the intent to be worn. The most popular concept of a lei in Hawaiian culture is a wreath of flowers draped around the neck presented upon arriving or leaving as a symbol of affection. This concept was popularized through tourism between the Hawaiian Islands and the continental United States in the 19th and 20th centuries.
Children and sweethearts are poetically referred to as "lei" and many ancient and modern songs and chants refer to this imagery.
Polynesian
In Polynesian cultures, a lei is something that is created by someone and given to another with the intent to decorate that person for an emotional reason—usually as a sign of affection. Common reasons include greeting, farewell, affection or love, friendship, appreciation, congratulation, recognition, or to otherwise draw attention to the recipient. In Samoa, a similar garland is called an 'Ula', in Tahiti it is referred to as 'Hei' and the Cook Islands it's called an 'Ei'.