The Hawaiian shirt is a style of dress shirt originating in Hawaii. It is currently the premier textile export of the Hawaii manufacturing industry. The shirts are printed, mostly short-sleeved, and collared. They usually have buttons, sometimes as a complete button-down shirt, and sometimes just down to the chest (pullover). Hawaiian shirts usually have a left chest pocket sewn in, often with attention to ensure the printed pattern remains continuous. Hawaiian shirts may be worn by men or women; women's Hawaiian shirts usually have a lower-cut, v-neck style. The lower hem is straight, as the shirts are not meant to be tucked in.

Hawaiian shirts exported to the mainland United States and elsewhere are often brilliantly colored with floral patterns or generic Polynesian motifs and are worn as casual, informal wear.

Traditional men's Hawaiian shirts manufactured for local Hawaiian residents are usually adorned with traditional Hawaiian quilt designs, tapa designs, and simple floral patterns in more muted colors. Contemporary Hawaiian shirts may have prints that do not feature any traditional Hawaiian quilt or floral designs and instead may have such elements as automobiles, drinks, sports team logos, or other elements arranged in the same pattern as a traditional Hawaiian shirt.

Hawaiian 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. Malahini (newcomers) and tourists (visitors) often wear designs of many bright colors while Kamaaina (or those who have been living in the islands for a long time) seem to prefer less busy patterns. These shirts often are printed on the interior, resulting in the muted color on the exterior, and are called "reverse print". For those not familiar, it may appear to be a defect in manufacturing as the shirt appears to be sewn together inside-out.

source: wikipedia.org