means A broad-brimmed Mexican or Spanish hat, traditionally made of straw or felt, designed to shield the wearer's face and neck from the sun.

from Straight from Spanish sombrero, meaning 'hat,' built on sombra, 'shade,' which itself likely traces back to Latin — possibly a blend of sub ('under') and umbra ('shadow'), that same umbra that gives us 'umbrella' and 'umbrage.' So at its root the word simply means 'shade-maker,' which is exactly what the hat does best.