Southwest has 9 different meanings across 3 categories:
the compass point midway between south and west; at 225 degrees
"The storm is approaching from the southwest, bringing heavy rain to our coastal town."
the southwestern region of the United States generally including New Mexico, Arizona, Texas, California, and sometimes Utah and Colorado
"After moving to the southwest for its mild winters and vibrant culture, Sarah quickly found herself immersed in the local art scene."
the direction corresponding to the southwestward compass point
"As we drove toward the sunset, the wind picked up from the southwest and cooled our faces."
a location in the southwestern part of a country, region, or city
"The family decided to spend their summer vacation in the southwest of France to explore the vineyards and historic villages."
The compass point halfway between south and west, specifically 225°, abbreviated as SW.
"The storm cloud bank was clearly moving in from the southwest toward our town at a steady pace."
In plain English: Southwest is the direction that is halfway between south and west.
"The strong winds came from the southwest yesterday afternoon."
situated in or oriented toward the southwest
"The house faces the sunset, so its windows are oriented directly toward the southwest."
Of or pertaining to the southwest; southwestern.
"The house features a distinctive southwest-style courtyard with stucco walls and arched doorways."
In plain English: Southwest means being located toward both the south and west directions at the same time.
"The house faces the southwest, so it gets very little afternoon sun."
Usage: Use this adjective before nouns, such as in southwest winds, rather than after them where you would use the adverbial form southwesterly. It specifically describes direction relative to a location's south and west quadrants without implying movement toward that area.
to, toward, or in the southwest
"After driving west for a while, we finally turned southwest to reach our destination near the mountains."
The word southwest comes from Middle English, which borrowed it directly from Old English by combining the words for "south" and "west." It entered the language as a straightforward directional term describing the region between those two cardinal points.