| ovary, dermoid cyst of the | Tumour that develops from a totipotential germ cell (a primary oocyte) retained within the egg sac (ovary). Being totipotential, that cell can give rise to all orders of cells necessary to form mature tissues and often recognizable structures such as hair, bone and sebaceous (oily) material, neural tissue and teeth. Dermoid cysts may occur at any age but the prime age of detection is in the childbearing years. The average age is 30. Up to 15% of women with ovarian teratomas have them in both ovaries. Dermoid cysts can range in size from a centimeter (less than a half inch) up to 45 cm (17 inches) in diameter. They can cause the ovary to twist (torsion) and imperil its blood supply. Although the large majority (about 98%) of ovarian teratomas are benign, the remaining fraction (about 2%) becomes cancerous (malignant). The larger the dermoid, the greater the risk of rupture with spillage of the greasy contents which can create problems with adhesions, pain etc. Removal is usually the treatment of choice by laparotomy (surgery) or laparoscopy (with a scope). Dermoid cysts of the ovary are also called simply dermoids or ovarian teratomas. (12 Dec 1998) |
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| ovate | Shaped like an egg in two dimensions, and attached by the wider end. Compare: ovoid. (09 Oct 1997) |
| ovation | 1. A lesser kind of triumph allowed to a commander for an easy, bloodless victory, or a victory over slaves. 2. Hence: An expression of popular homage; the tribute of the multitude to a public favorite. "To rain an April of ovation round Their statues." (Tennyson) Origin: L. Ovatio, fr. Ovare to exult, rejoice, triumph in an ovation; cf. Gr. To shout: cf. F. Ovation. Source: Websters Dictionary (01 Mar 1998) |
| oven dry ton | An amount of wood that weighs 2,000 pounds at zero percent moisture content. (05 Dec 1998) |
| ovenbird | <ornithology> Any species of the genus Furnarius, allied to the creepers. They inhabit South America and the West Indies, and construct curious oven-shaped nests. In the United States, Seiurus aurocapillus; called also golden-crowned thrush. In England, sometimes applied to the willow warbler, and to the long-tailed titmouse. (06 Mar 1998) |
| overall | A single citation covering several articles of various degrees of specificity or a single citation covering papers presented at a meeting. A subject overall refers to a series of articles on a single subject; a congress overall refers to papers presented at a formal local, regional, national, or international gathering; a society overall refers to papers presented at an annual, semi-annual, monthly, weekly, or other meeting of a society, academy, institute, hospital, etc. The publication type may be used for a single citation with or without the additional indexing or cataloging of individual papers. The individual papers, however, are not labelled overall. (12 Dec 1998) |
| overall response rate | <pharmacology> Sum of complete and partial tumour responses seen in a study, divided by the number of evaluable patients. (05 Jan 1998) |
| overanxious disorder | A mental disorder of childhood or adolescence marked by excessive worrying and fearful behaviour not related specifically to separation or due to recent stress. (05 Mar 2000) |
| overbalance | Excess of weight or value; something more than an equivalent; as, an overbalance of exports. Source: Websters Dictionary (01 Mar 1998) |
| overbank flooding | <ecology> Any situation in which inundation occurs as a result of the water level of a river or stream rising above bank level. (05 Jan 1998) |
| overbear | To bear fruit or offspring to excess; to be too prolific. Source: Websters Dictionary (01 Mar 1998) |
| overbite | <dentistry> Vertical overlapping of the upper teeth over the lower. (08 Jan 1998) |
| overclosure | A decrease in occlusal vertical dimension. (05 Mar 2000) |
| overcome | 1. To get the better of; to surmount; to conquer; to subdue; as, to overcome enemies in battle. "This wretched woman overcome Of anguish, rather than of crime, hath been." (Spenser) 2. To overflow; to surcharge. 3. To come or pass over; to spreads over. "And overcome us like a summer's cloud." (Shak) Synonym: To conquer, subdue, vanquish, overpower, overthrow, overturn, defeat, crush, overbear, overwhelm, prostrate, beat, surmount. See Conquer. Origin: AS. Ofercuman. See Over, Come, and cf. Supervene. Source: Websters Dictionary (01 Mar 1998) |
| overcompensation | 1. An exaggeration of personal capacity by which one overcomes a real or imagined inferiority. 2. The process in which a psychologic deficiency inspires exaggerated correction. See: compensation. (05 Mar 2000) |