| rosetta wood | An east Indian wood of a reddish orange colour, handsomely veined with darker marks. It is occasionally used for cabinetwork. Source: Websters Dictionary (01 Mar 1998) |
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| rosette | <dermatology> A group of organs or other body features, such as leaves or hair, which are clustered and crowned around a common point of attachment. (09 Oct 1997) |
| rosette formation | The in vitro formation of clusters consisting of a cell (usually a lymphocyte) surrounded by antigenic cells or antigen-bearing particles (usually erythrocytes, which may or may not be coated with antibody or antibody and complement). The rosette-forming cell may be an antibody-forming cell, a memory cell, a T-cell, a cell bearing surface cytophilic antibodies, or a monocyte possessing fc receptors. Rosette formation can be used to identify specific populations of these cells. (12 Dec 1998) |
| rosette test | A test for rosette-forming cells (T-lymphocytes) in which these cells and sheep erythrocytes, are incubated and centrifuged lightly, then examined under a microscope for rosette formation or adherence of erythrocytes to T lymphocytes. (05 Mar 2000) |
| rosette-forming cells | T lymphocytes with an affinity for sheep erythrocytes and which, when suspended in serum, bind the uncoated, nonsensitised erythrocytes in a rosette formation. (05 Mar 2000) |
| rosewood | A valuable cabinet wood of a dark red colour, streaked and variegated with black, obtained from several tropical leguminous trees of the genera Dalbergia and Machaerium. The finest kind is from Brazil, and is said to be from the Dalbergia nigra. African rosewood, the wood of the leguminous tree Pterocarpus erinaceus. Jamaica rosewood, the wood of two West Indian trees (Amyris balsamifera, and Linocieria ligustrina). New South Wales rosewood, the wood of Trichilia glandulosa, a tree related to the margosa. Source: Websters Dictionary (01 Mar 1998) |
| roseworm | <zoology> The larva of any one of several species of lepidopterous insects which feed upon the leaves, buds, or blossoms of the rose, especially Cacaecia rosaceana, which rolls up the leaves for a nest, and devours both the leaves and buds. Source: Websters Dictionary (01 Mar 1998) |
| rosewort | <botany> Roseroot. Any plant nearly related to the rose. Source: Websters Dictionary (01 Mar 1998) |
| rosin | The hard, amber-coloured resin left after distilling off the volatile oil of turpentine; colophony. Rosin oil, an oil obtained from the resin of the pine tree, used by painters and for lubricating machinery, etc. Origin: A variant of resin. Source: Websters Dictionary (01 Mar 1998) |
| rosinweed | <botany> The compass plant. See Compass. A name given in California to various composite plants which secrete resins or have a resinous smell. Source: Websters Dictionary (01 Mar 1998) |
| rosmarine | 1. Dew from the sea; sea dew. "That purer brine And wholesome dew called rosmarine." (B. Jonson) 2. Rosemary. "Biting on anise seed and rosmarine." Origin: OE. See Rosemary. Source: Websters Dictionary (01 Mar 1998) |
| rosolic | <chemistry> Pertaining to, or designating, a complex red dyestuff (called rosolic acid) which is analogous to rosaniline and aurin. It is produced by oxidizing a mixture of phenol and cresol, as a dark red amorphous mass, C20H16O3, which forms weak salts with bases, and stable ones with acids. Synonym: methyl aurin, and, formerly, corallin. Origin: Rose + carbolic. Source: Websters Dictionary (01 Mar 1998) |
| ross | 115), [Etymol. Uncertain. The rough, scaly matter on the surface of the bark of trees. Source: Websters Dictionary (01 Mar 1998) |
| Ross cycle | The life cycle of the malaria parasite. (05 Mar 2000) |
| Ross River fever | A mild febrile illness of humans in Australia characterised by polyarthralgia and rash, caused by the Ross River virus, a member of the family Togaviridae, and transmitted by mosquitoes. Synonym: epidemic exanthema, Murray Valley rash, Ross River fever. (05 Mar 2000) |