| or | A particle that marks an alternative; as, you may read or may write, that is, you may do one of the things at your pleasure, but not both. It corresponds to either. You may ride either to London or to Windsor. It often connects a series of words or propositions, presenting a choice of either; as, he may study law, or medicine, or divinity, or he may enter into trade. "If man's convenience, health, Or safety interfere, his rights and claims Are paramount." (Cowper) Or may be used to join as alternatives terms expressing unlike things or ideas (as, is the orange sour or sweet?), or different terms expressing the same thing or idea; as, this is a sphere, or globe. Or sometimes begins a sentence. In this case it expresses an alternative or subjoins a clause differing from the foregoing. "Or what man is there of you, who, if his son shall ask him for a loaf, will give him a stone?" Or for either is archaic or poetic. "Maugre thine heed, thou must for indigence Or steal, or beg, or borrow thy dispence." (Chaucer) Origin: OE. Or, outher, other, auther, either, or, AS. Awer, contr. From ahwaeer; a aye + hwaeer whether. See Aye, and Whether, and cf. Either. Source: Websters Dictionary (01 Mar 1998) |
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| ora | Plural of L. Os, the mouth. An edge or a margin. Origin: L. (05 Mar 2000) |
| ora serrata | The serrated extremity of the optic part of the retina, located a little behind the ciliary body and marking the limits of the percipient portion of the membrane. (05 Mar 2000) |
| Orabase | <chemical> Used in therapy of oral mucosal ulcers (26 Jun 1999) |
| orabassu | <zoology> A South American monkey of the genus Callithrix, especially. Source: Websters Dictionary (01 Mar 1998) |
| orache | <botany> A genus (Atriplex) of herbs or low shrubs of the Goosefoot family, most of them with a mealy surface. Garden orache, a plant (Atriplex hortensis), often used as a pot herb; also called mountain spinach. Origin: F. Arroche, corrupted fr. L. Atriplex, Gr. Cf. Arrach. Source: Websters Dictionary (01 Mar 1998) |
| orad | 1. In a direction toward the mouth. 2. Situated nearer the mouth in relation to a specific reference point; opposite of aborad. Origin: L. Os, mouth, + ad, to (05 Mar 2000) |
| oral | <anatomy> Pertaining to the mouth, taken through or applied in the mouth, as an oral medication or an oral thermometer. (18 Nov 1997) |
| oral (erosive) lichen planus | Oral manifestations of lichen planus characterised by white striae (Wickham's striae) of the oral mucous membrane and sometimes associated with ulceration; patients may or may not exhibit a history of cutaneous lichen planus. (05 Mar 2000) |
| oral biology | That aspect of biology devoted to the study of biological phenomena associated with the oral cavity in health and disease (e.g., dental caries, mastication, periodontal disease). (05 Mar 2000) |
| oral cancer | Cancer within the mouth. Please see MedicineNet site on ral cancer for more information. (12 Dec 1998) |
| oral candidiasis | <gastroenterology, microbiology, oncology> Infection with a fungus of the genus Candida. It is usually a superficial infection of the moist cutaneous areas of the body and is generally caused by Candida albicans, it most commonly involves the skin (dermatocandidiasis), oral mucous membranes (oral candidiasis), respiratory tract (bronchocandidiasis) and vagina (vaginal candidiasis or thrush). Rarely there is a systemic infection or endocarditis. Oral candidiasis: describes a fungal (yeast) infection of the oral cavity due to Candida. It is common in infants, diabetics or those on chemotherapy and is well recognised in patients with HIV infection and AIDS. Oesophageal candidiasis: Infection of the oesophagus by the yeast-like fungus Candidal albicans. Usually occurs in the immunocompromised individual (AIDS or following chemotherapy). Oral candidiasis is a predisposing factor but oesophageal involvement can occur without evidence of infection in the oral cavity. Symptoms include difficulty swallowing, pain on swallowing and oral lesions. Diagnosis is made using endoscopy. Treatment is with antifungal agents such as ketoconazole or fluconazole. Synonym: moniliasis, candidosis, oidiomycosis, blastodendriosis. (16 Dec 1997) |
| oral cavity | The region consisting of the vestibulum oris, the narrow cleft between the lips and cheeks, and the teeth and gums, and the cavitas oris propria. Synonym: cavitas oris, cavum oris, mouth. (05 Mar 2000) |
| oral cavity proper | The space between the dental arches, limited posteriorly by the isthmus of the fauces (palatoglossal arch). Synonym: cavitas oris propria. (05 Mar 2000) |
| oral cholecystogram | <radiology> Dose: 6 x 0.5 gram tablets after evening meal, peak opacification in 14-19 hrs. (13-35% excreted in urine) patient selection: bilirubin less than 5mg% (unless secondary to haemolysis), contraindicated in serious liver disease, relative contraindications in peritonitis, postoperative ileus, acute pancreatitis nonvisualization of gallbladder, cholecytectomy, obstruction of cystic duct, chronic cholecystitis, anomolous position of gall bladder, extrabiliary causes, fasting state, failure to reach absorptive surface of bowel (e.g. Malabsorption), deficiency of bile salts (Crohn disease, surgical resection of TI, liver disease, cholestyramine therapy, abnormal communication between biliary and GI tract) (12 Dec 1998) |