| orangery | A place for raising oranges; a plantation of orange trees. Origin: F. Orangerie, fr. Orange. See Orange. Source: Websters Dictionary (01 Mar 1998) |
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| orangite | <chemical> An orange-yellow variety of the mineral thorite, found in Norway. Source: Websters Dictionary (01 Mar 1998) |
| oratorian | See Fathers of the Oratory, under Oratory. Origin: Cf. F. Oratorien. Source: Websters Dictionary (01 Mar 1998) |
| oratory | Origin: OE. Oratorie, fr. L. Oratorium, fr. Oratorius of praying, of an orator: cf. F. Oratoire. See Orator, Oral, and cf. Oratorio. A place of orisons, or prayer; especially, a chapel or small room set apart for private devotions. "An oratory [temple] . . . In worship of Dian." (Chaucer) "Do not omit thy prayers for want of a good oratory, or place to pray in." (Jer. Taylor) Fathers of the Oratory, a society of priests founded by St. Philip Neri, living in community, and not bound by a special vow. The members are called also oratorians. Source: Websters Dictionary (01 Mar 1998) |
| oratress | A woman who makes public addresses. Source: Websters Dictionary (01 Mar 1998) |
| oratrix | A woman plaintiff, or complainant, in equity pleading. Origin: L. Source: Websters Dictionary (01 Mar 1998) |
| Orbeli effect | The fatigue of a muscle stimulated by its nerve (i.e., indirectly) is reduced by concurrent stimulation of sympathetic fibres to the muscle; thought to be caused by norepinephrine diffusing from adrenergic fibres which innervate blood vessels in the muscle. (05 Mar 2000) |
| Orbeli, Leon | <person> Russian physiologist, 1882-1958. See: Orbeli effect. (05 Mar 2000) |
| orbicula | <zoology> Same as Discina. Origin: NL. See Orbicle. Source: Websters Dictionary (01 Mar 1998) |
| orbicular | Circular or nearly so. (09 Oct 1997) |
| orbicular bone | A knob at the tip of the long limb of the incus which articulates with the stapes. Synonym: processus lenticularis incudis, lenticular apophysis, lenticular bone, orbicular bone, orbicular process, orbiculare, os orbiculare, os sylvii. (05 Mar 2000) |
| orbicular ligament | <anatomy> One of a number of ligament's encircling various parts; the principal annular ligament's are those of the stapes, radius, and trachea. See: annular ligament of the radius, annular ligament of the stapes, annular ligaments of the trachea. Synonym: ligamentum annulare, orbicular ligament. (05 Mar 2000) |
| orbicular ligament of radius | The ligament that encircles and holds the head of the radius in the radial notch of the ulna, forming the proximal radioulnar joint and enabling pronation/supination of forearm; receives the radial collateral ligament of the elbow. Synonym: ligamentum annulare radii, ligamentum orbiculare radii, orbicular ligament of radius. (05 Mar 2000) |
| orbicular muscle | <anatomy> A sphincter-like sheet of muscle that encircles an orifice such as the mouth or the palpebral fissures. Synonym: musculus orbicularis, orbicular muscle, orbicularis. (05 Mar 2000) |
| orbicular muscle of eye | <anatomy> Consists of three portions: orbital part, or external portion, which arises from frontal process of maxilla and nasal process of frontal bone, encircles aperture of orbit, and is inserted near origin; palpebral part, or internal portion, which arises from medial palpebral ligament, passes through each eyelid, and is inserted into lateral palpebral raphe; lacrimal part (tensor tarsi muscle, Duverney's or Horner's muscle) arises from posterior lacrimal crest and passes across lacrimal sac to join palpebral portion; action, closes eye, wrinkles forehead vertically; nerve supply, facial. Synonym: musculus orbicularis oculi, musculus orbicularis palpebrarum, orbicular muscle of eye, sphincter oculi. (05 Mar 2000) |