| rhein | <chemistry> Chrysophanic acid. Source: Websters Dictionary (01 Mar 1998) |
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| Rheinberg filter | <equipment> A colour-filter disk to be placed, as a dark field stop would be placed, below the substage condenser. The central circular area, that is filled with one of the two or three colour filters, should safely subtend the objective aperture. The annular quadrants around this are normally contrasting in colour. This is/are the colour shown by the organisms or other specimen detail against the coloured field. The effect is one kind of optical staining. (05 Aug 1998) |
| Rheinberg microscope | <instrument> A modified form of dark-field microscope in which the central opaque stop in the condenser is replaced by a coloured filter, producing a background of contrasting colour against which the specimen is illuminated. (05 Mar 2000) |
| rheinberry | <botany> One of the berries or drupes of the European buckthorn; also, the buckthorn itself. Origin: G. Rheinbeere. Source: Websters Dictionary (01 Mar 1998) |