crown glass

American  

noun

1. an optical glass of low dispersion and generally low index of refraction.

2. an old form of window glass formed by blowing a globe and whirling it into a disk.

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crown glass British  

noun

1. another name for optical crown

2. an old form of window glass made by blowing a globe and spinning it until it formed a flat disc

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Etymology

Origin of crown glass

First recorded in 1700–10

Example Sentences

"We've looked everywhere and can't find anyone that can cast crown glass," he said.

From BBC • Oct. 23, 2017

What is the ratio of thicknesses of crown glass and water that would contain the same number of wavelengths of light?

From Textbooks • Aug. 12, 2015

What is Brewster’s angle for light traveling in water that is reflected from crown glass?

From Textbooks • Aug. 12, 2015

Suppose Figure 25.53 represents a ray of light going from air through crown glass into water, such as going into a fish tank.

From Textbooks • Aug. 12, 2015

"What is crown glass?" whispered Jean to Giusippe.

From The Story of Glass by Gray, C.P.