| um | Symbol for micromolar. Symbol for micrometer. (05 Mar 2000) |
|---|---|
| umbel | <plant biology> A racemose inflorescence in which all the individual flower stalks arise in a cluster at the top of the peduncle and are of about equal length. (09 Oct 1997) |
| umbellar | <botany> Of or pertaining to an umbel; having the form of an umbel. Source: Websters Dictionary (01 Mar 1998) |
| umbellate | Bearing umbels, consisting of umbels, forming an umbel or umbels. (09 Oct 1997) |
| umbellated | <botany> Bearing umbels; pertaining to an umbel; umbel-like; as, umbellate plants or flowers. Origin: NL. Umbellatus. Source: Websters Dictionary (01 Mar 1998) |
| umbellet | <botany> A small or partial umbel; an umbellule. Source: Websters Dictionary (01 Mar 1998) |
| umbellic | <chemistry> Pertaining to, or obtained from, certain umbelliferous plants; as, umbellic acid. Umbellic acid. <chemistry> Anisic acid. A yellow powder obtained from umbelliferone. Source: Websters Dictionary (01 Mar 1998) |
| umbellifer | <botany> A plant producing an umbel or umbels. Origin: NL. See Umbelliferous. Source: Websters Dictionary (01 Mar 1998) |
| umbelliferone | <chemistry> A tasteless white crystalline substance, C9H6O3, found in the bark of a certain plant (Daphne Mezereum), and also obtained by the distillation of certain gums from the Umbelliferae, as galbanum, asafetida, etc. It is analogous to coumarin. Synonym: hydroxy-coumarin. Source: Websters Dictionary (01 Mar 1998) |
| umbelliferones | 7-hydroxycoumarins. Substances present in many plants, especially umbelliferae. Umbelliferones are used in sunscreen preparations and may be mutagenic. Their derivatives are used in liver therapy, as reagents, plant growth factors, sunscreens, insecticide, parasiticides, choleretics, spasmolytics, etc. (12 Dec 1998) |
| umbelliferous | <botany> Producing umbels. Of or pertaining to a natural order (Umbelliferae) of plants, of which the parsley, carrot, parsnip, and fennel are well-known examples. Origin: Umbel: cf. F. Ombillifere. Source: Websters Dictionary (01 Mar 1998) |
| umbellularia | <zoology> A genus of deep-sea alcyonaria consisting of a cluster of large flowerlike polyps situated at the summit of a long, slender stem which stands upright in the mud, supported by a bulbous base. Origin: NL. Umbellule. Source: Websters Dictionary (01 Mar 1998) |
| umbellule | <botany> An umbellet. Origin: NL. Umbellula, dim. Of umbella: cf. F. Ombellule. Source: Websters Dictionary (01 Mar 1998) |
| umber | 1. A brown or reddish pigment used in both oil and water colours, obtained from certain natural clays variously coloured by the oxides of iron and manganese. It is commonly heated or burned before being used, and is then called burnt umber; when not heated, it is called raw umber. See Burnt umber, below. 2. An umbrere. 3. [F. Ombre, umbre, L. Umbra. <zoology> See Grayling. 4. [Cf. NL. Scopus umbretta, F. Ombrette; probably fr. L. Umbra shade, in allusion to its dark brown colour. See Umber a pigment. <zoology> An African wading bird (Scopus umbretta) allied to the storks and herons. It is dull dusky brown, and has a large occipital crest. Called also umbrette, umbre, and umber bird. Burnt umber, a pigment made by burning raw umber, which is changed by this process from an olive brown to a bright reddish brown. Cologne, or German, umber, a brown pigment obtained from lignite. See Cologne earth. Origin: F. Ombre ocherous ore of iron, terre d'ombre, It. Terra d'ombra, literally, earth of shadow or shade, L. Umbra shadow, shade. Cf. Umber, 3 & 4, Umbrage. Source: Websters Dictionary (01 Mar 1998) |
| umber codon | The termination codon UGA. Synonym: opal codon. (05 Mar 2000) |