Definition of stroma in English:

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Pronunciation: /ˈstrōmə/

noun (plural stromata /-mətə/)

1 Anatomy & Biology The supportive tissue of an epithelial organ, tumor, gonad, etc., consisting of connective tissues and blood vessels.
Example sentences
  • Loose connective tissue stroma predominated in the less cellular areas.
  • The stroma consists of fatty tissue and ligaments surrounding the ducts and lobules, blood vessels and lymphatic vessels.
  • The deeper regions of the tumor showed hypocellularity and had an abundance of loose edematous stroma.
1.1The spongy framework of protein fibers in a red blood cell or platelet.
Example sentences
  • The endometrial stroma has a framework consisting of reticular fibers and stromal cells.
  • The surrounding stroma was infiltrated by plasma cells and scattered aggregates of lymphocytes, forming follicles with germinal centres.
  • Typical plaques showed proliferation of myofibroblastic cells with myxoid stroma.
1.2 Botany The matrix of a chloroplast, in which the grana are embedded.
Example sentences
  • Chloroplast envelopes, stacked grana and unstacked stroma thylakoids were well-defined.
  • There is characteristically a dense sparsely cellular fibrous stroma.
  • Granules of different sizes were noted in the chloroplast stroma in all treatments.
2 Botany A cushionlike mass of fungal tissue, having spore-bearing structures either embedded in it or on its surface.
Example sentences
  • This latter consisted of a few membranes irregularly distributed in the stroma or tightly pressed to form very electron-dense stacks.
  • During in vivo measurements, excitation light is incident upon the epithelium, and must travel through this tissue layer before reaching the stroma.
  • Transport proteins in the inner plastid envelope membrane connect the metabolism of plastid stroma and surrounding cytoplasm.



(chiefly Anatomy )
Example sentences
  • A complete description of ovarian endometrial stromal sarcomas, adenosarcomas, and carcinosarcomas is presented.
  • The drug has also proved effective against rare gastrointestinal stromal tumours and small-cell lung cancers.
  • The prostate specimen showed glandular and stromal hyperplasia.


Pronunciation: /strōˈmatik/
(chiefly Botany )
Example sentences
  • Exposure to two UV-B doses induced a notable increase in the grana-stromatic lamella ratio and luminal space dilation of the stromatic lamellas.
  • The ncosomes in the sample are 1-10 cm thick, stromatic, and contain melanosomes at their margins.


Mid 19th century: modern Latin, via late Latin from Greek strōma 'coverlet'.

For editors and proofreaders

Syllabification: stro·ma

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