The Aloha shirt is a style of dress shirt originating in Hawaii. It is currently the premier textile export of the Hawaii manufacturing industry. The lower hem is straight, as the shirts are not meant to be tucked in.
Aloha shirts exported to the mainland United States and elsewhere are called Hawaiian shirts and often brilliantly colored with floral patterns or generic Polynesian motifs and are worn as casual, informal wear.
By contrast, women's aloha shirts manufactured for local Hawaiian residents are usually adorned with traditional Hawaiian quilt designs, tapa designs, or simple floral patterns in more muted colors. Aloha shirts manufactured for local consumption are considered formal wear in business and government, and thus are regarded as equivalent to a shirt, coat, and tie (generally impractical in the warmer climate of Hawaii) in all but the most formal of settings.
The related concept of "Aloha Attire" stems from the Aloha shirt. Semi-formal functions such as weddings, birthday parties, and dinners are often designated as "Aloha Attire". Because Hawaii tends to be more casual, it is rarely appropriate to attend such functions in full evening wear like on the mainland; instead, Aloha Attire is seen as the happy medium between excessive formality and casual wear. "Aloha Friday," a now-common tradition of celebrating the end of the workweek by wearing more casual attire on Fridays, initially grew out of an effort to promote aloha shirts.