| precalciferol | The immediate precursor of ergocalciferol and lumisterol. (05 Mar 2000) |
|---|---|
| precancer | A lesion from which a malignant neoplasm is believed to develop in a significant number of instances, and which may or may not be recognizable clinically or by microscopic changes in the affected tissue. (05 Mar 2000) |
| precancerous | <pathology> In a very early stage of cancer development and abnormal changes occur in tissue as a pre-determinant for possible future malignancy. (31 Dec 1997) |
| precancerous conditions | Pathological processes that tend eventually to become malignant. (12 Dec 1998) |
| precancerous lesion | A noninvasive lesion with a predictable likelihood of becoming malignant; e.g., actinic keratosis. (05 Mar 2000) |
| precancerous melanosis of Dubreuilh | An obsolete term for lentigo maligna. (05 Mar 2000) |
| precapillary | Preceding a capillary;an arteriole or venule. (05 Mar 2000) |
| precapillary anastomosis | An anastomosis between arterioles just before they become capillaries. (05 Mar 2000) |
| precapillary pulmonary hypertension | <radiology> Vascular: increased flow (left to right shunts), decreased flow (tetralogy of Fallot), primary pulmonary hypertension, thromboembolic disease, pulmonary arteritides, Pleuropulmonary: emphysema, diffuse lung disease, fibrothorax, chest deformity, hypoventilation, high-altitude pulmonary hypertension (12 Dec 1998) |
| precardiac | Anterior to the heart. (05 Mar 2000) |
| precardinal | Relating to the anterior cardinal veins. (05 Mar 2000) |
| precarious | 1. Depending on the will or pleasure of another; held by courtesy; liable to be changed or lost at the pleasure of another; as, precarious privileges. 2. Held by a doubtful tenure; depending on unknown causes or events; exposed to constant risk; not to be depended on for certainty or stability; uncertain; as, a precarious state of health; precarious fortunes. "Intervals of partial and precarious liberty." Synonym: Uncertain, unsettled, unsteady, doubtful, dubious, equivocal. Precarious, Uncertain. Precarious in stronger than uncertain. Derived originally from the Latin precari, it first signified "granted to entreaty," and, hence, "wholly dependent on the will of another." Thus it came to express the highest species of uncertainty, and is applied to such things as depend wholly on future casualties. Preca"riously, Preca"riousness. Origin: L. Precarius obtained by begging or prayer, depending on request or on the will of another, fr. Precari to pray, beg. See Pray. Source: Websters Dictionary (01 Mar 1998) |
| precartilage | A closely packed aggregation of mesenchymal cells just prior to their differentiation into embryonic cartilage. (05 Mar 2000) |
| precava | <anatomy> The major venous channel draining the thorax and head which ends in the right atrium. (19 Jan 1998) |
| precedential | Of the nature of a precedent; having force as an example for imitation; as, precedential transactions. "All their actions in that time are not precedential to warrant posterity." (Fuller) Source: Websters Dictionary (01 Mar 1998) |