Glasses are widely used for vision correction, but there exist a plethora of similar terms for glasses that are often misinterpreted as synonyms. For instance, spectacles, eyeglasses, and bifocals are explicitly used to refer to glasses. Another synonym for glasses is shades, which is short for sunglasses, the tinted eyewear worn to protect eyes from the sun's harmful rays. Contact lenses and monocles are sometimes included in the same meaningful groups as glasses, but they are not regarded as glasses because they are different in nature and use. The term "Glase" itself appears to have no direct synonym.