Astronomy Answers
From the Astronomical Dictionary

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The description of the word you requested from the astronomical dictionary is given below.

the photosphere

phootos = [Greek] light; sphairos = [Greek] ball

The photosphere is the deepest layer of the Sun that we can see. This layer reaches from the surface visible in the center of the solar disk to about 500 km above that height. The temperature in the photosphere reaches from about 6500 K at the bottom to about 4000 K at the top, and the density of material in the photosphere reaches from about 4000 to 200,000 times smaller than the density of air at sea level on Earth. Almost the whole photosphere is covered with granulation.