chromosphere

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An incandescent, transparent layer of gas, primarily hydrogen, several thousand miles in depth, lying above and surrounding the photosphere of a star, such as the sun, but distinctly separate from the corona.
• noun A gaseous layer similar to a chromosphere around a star.

from The Century Dictionary.

• noun A rose-colored gaseous envelop around the body of the sun, through which the light of the photosphere passes, and from which the enormous red cloud-masses of flames of hydrogen, called solar protuberances, are at times thrown up. Also chromatosphere, color-sphere, and sierra.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Astron.) An atmosphere of rare matter, composed principally of incandescent hydrogen gas, surrounding the sun and enveloping the photosphere. Portions of the chromosphere are here and there thrown up into enormous tongues of flame.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun astronomy The faint pink extension of a star's atmospheric envelope between the corona and the photosphere

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a gaseous layer of the sun's atmosphere (extending from the photosphere to the corona) that is visible during a total eclipse of the sun