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asteroid belt
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Asti Spumante
astigmatism
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astigmatism

a·stig·ma·tism [ ə stígmə tìzzəm ]


noun 
Definition:
 
1. cause of blurred vision: an unequal curving of one or more of the refractive surfaces of the eye, usually the cornea. It prevents light rays lying in specific planes from coming to a focus on the retina, thus producing blurred vision.

2. optical lens defect: a defect in a lens or mirror that prevents light rays from meeting at a single point, producing an imperfect image

[Mid-19th century. <a3 + Greek stigmat- "point"]

as·tig·mat·ic [ àstig máttik ] adjective
as·tig·mat·i·cal·ly [ àstig máttikəlee ] adverb
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