granule

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granule,

in astronomy: see photospherephotosphere,
luminous, apparently opaque layer of gases that forms the visible surface of the sun or any other star. The photosphere lies between the dense interior gases and the more attenuated gases of the chromosphere.
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granule

[′gran·yül]
(astronomy)
A convective cell in the solar photosphere, about 600 miles (1000 kilometers) in diameter.
(geology)
A somewhat rounded rock fragment ranging in diameter from 2 to 4 millimeters; larger than a coarse sand grain and smaller than a pebble.

granule

Geology a single rock fragment in gravel, smaller than a pebble but larger than a sand grain
References in periodicals archive ?
Although Birbeck granules are the hallmark of Langerhans cells and lesional cells of PLCH, the typical morphologic features and the availability of sensitive and specific immunostains makes the analysis of the cellular ultrastructure unnecessary for the diagnosis of PLCH.
As LCH is also a proliferating disorder of Langerhans cells, LCH stains positive for CD1a and S-100 protein, and at times exhibits Birbeck granules, as does LCS.
The Birbeck granule, a trilaminar rod-like organelle with a terminal expansion resembling a tennis racquet, is distinctive.
Some clinicians believe that the cells are precursors to Langerhans' cells, obtaining Birbeck granules as they climb into the epidermis.
Electron micrograph of follicular dendritic cell sarcoma shows well-developed, long interdigitating cytoplasmic processes and desmosome-like junctions; no Birbeck granules are seen (original magnification X20 000).