| primordial kidney | 1. The definitive excretory organ of primitive fishes. Synonym: head kidney. 2. In the embryos of higher vertebrates, a vestigial structure consisting of a series of tortuous tubules emptying into the cloaca by way of the primary nephric duct; in the human embryo, the pronephros is a very rudimentary and temporary structure, followed by the mesonephros and still later by the metanephros. Synonym: forekidney, primordial kidney. Origin: pro-+ G. Nephros, kidney (05 Mar 2000) |
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| primordial ovarian follicle | A follicle in which the primordial oocyte is surrounded by a single layer of flattened follicular cells. (05 Mar 2000) |
| primordian | <botany> A name given to several kinds of plums; as, red primordian, amber primordian, etc. Origin: L. Primordius first of all, fr. Primordium. Source: Websters Dictionary (01 Mar 1998) |
| primordium | An aggregation of cells in the embryo indicating the first trace of an organ or structure. Synonym: anlage. Origin: L. Origin, fr. Primus, first, + ordior, to begin (05 Mar 2000) |
| primosome | <molecular biology> Complex of proteins involved in the synthesis of the RNA primer sequences used in DNA replication. Main components are primase and DNA helicase that move as a unit with the replication fork. Origin: Gr. Soma = body (18 Nov 1997) |
| primrose | <botany> An early flowering plant of the genus Primula (P. Vulgaris) closely allied to the cowslip. There are several varieties, as the white-, the red-, the yellow-flowered, etc. Formerly Synonym: primerole, primerolles. Any plant of the genus Primula. Evening primrose, an erect biennial herb (Enothera biennis), with yellow vespertine flowers, common in the United States. The name is sometimes extended to other species of the same genus. Primrose peerless, the two-flowered Narcissus (N. Biflorus). Origin: OE. Primerole, F. Primerole, a derivative fr. LL. Primula, from L. Primus first. See Prime. Source: Websters Dictionary (01 Mar 1998) |
| primula | <botany> The genus of plants including the primrose (Primula vera). Origin: LL. See Primrose. Source: Websters Dictionary (01 Mar 1998) |
| primulaceous | <botany> Of or pertaining to an order of herbaceous plants (Primulaceae), of which the primrose is the type, and the pimpernel, the cyclamen, and the water violet are other examples. Source: Websters Dictionary (01 Mar 1998) |
| primulin | An acid yellow thiazole dye, C21H14N3O3Na, used as a fluorescent vital stain. (05 Mar 2000) |
| primum mobile | <astronomy> In the Ptolemaic system, the outermost of the revolving concentric spheres constituting the universe, the motion of which was supposed to carry with it all the inclosed spheres with their planets in a daily revolution from east to west. See Crystalline heavens, under Crystalline. "The motions of the greatest persons in a government ought to be, as the motions of the planets, under primum mobile." (Bacon) Origin: L, first cause of motion. Source: Websters Dictionary (01 Mar 1998) |
| primus | First; denoting the first of a series of similar structures. Origin: L. (05 Mar 2000) |
| prince | 1. The one of highest rank; one holding the highest place and authority; a sovereign; a monarch; originally applied to either sex, but now rarely applied to a female. "Go, Michael, of celestial armies prince." (Milton) "Queen Elizabeth, a prince admirable above her sex." (Camden) 2. The son of a king or emperor, or the issue of a royal family; as, princes of the blood. 3. A title belonging to persons of high rank, differing in different countries. In England it belongs to dukes, marquises, and earls, but is given to members of the royal family only. In Italy a prince is inferior to a duke as a member of a particular order of nobility; in Spain he is always one of the royal family. 4. The chief of any body of men; one at the head of a class or profession; one who is preeminent; as, a merchant prince; a prince of players. "The prince of learning." Prince-Albert coat, a long double-breasted frock coat for men. Prince of the blood, Prince consort, Prince of darkness. See Blood, Consort, and Darkness. Prince of Wales, the oldest son of the English sovereign. <botany> Prince's feather See Pipsissewa. Origin: F, from L. Princeps, -cipis, the first, chief; primus first + capere to take. See Prime, and Capacious. Source: Websters Dictionary (01 Mar 1998) |
| prince edward island | An island in the gulf of st. Lawrence constituting a province of canada in the eastern part of the country. It is very irregular in shape with many deep inlets. Its capital is charlottetown. Discovered by the french in 1534 and originally named ile saint-jean, it was renamed in 1799 in honor of prince edward, fourth son of george III and future father of queen victoria. (12 Dec 1998) |
| princeps | Principal; in anatomy, term used to distinguish several arteries. Origin: L. Chief, fr. Primus, first, + capio, to take, choose (05 Mar 2000) |
| princeps cervicis | <anatomy, artery> Origin: occipital artery within occipital groove; distribution: posterior neck muscles and cervical trapezius muscle; anastomoses: superficial and deep cervical arteries, vertebral artery. Synonym: ramus descendens arteriae occipitalis, princeps cervicis artery, princeps cervicis. (05 Mar 2000) |