sunglasses

[suhn-glas-iz, -glah-siz] /ˈsʌnˌglæs ɪz, -ˌglɑ sɪz/
plural noun
1.
eyeglasses with colored or tinted lenses that protect the eyes from the glare of sunlight.
Origin
1800-10; sun + glasses

sunglass1

[suhn-glas, -glahs] /ˈsʌnˌglæs, -ˌglɑs/
noun
1.
burning glass.
Origin
1800-10; sun + glass
British Dictionary definitions for sunglasses

sunglasses

/ˈsʌnˌɡlɑːsɪz/
plural noun
1.
glasses with darkened or polarizing lenses that protect the eyes from the sun's glare

sunglass

/ˈsʌnˌɡlɑːs/
noun
1.
a convex lens used to focus the sun's rays and thus produce heat or ignition; burning glass
Word Origin and History for sunglasses
n.

1917, from sun (n.) + glasses. Earlier sunglass (1804) meant a burning glass.