Commonly used to refer to the
Southwestern part of the
United States, generally considered to include
Arizona,
Utah,
New Mexico,
Texas,
Nevada, and
Southern California. These
states experience the hottest
temperatures that the
USA has to offer, particularly
Arizona, which usually has the highest
thermometer readings of any other inhabited location in the US.
"Southwest" referring to art or culture usually means Arizona, New Mexico, Mexico, and maybe El Paso, Texas, as far as I can tell. Most artwork, food, architecture, or whatever that is labelled "Southwestern" is a sickly combination of Mexican and Native American cultural influences.
And for a minority of people, it just means the Sonoran Desert.