| half and half nail | Division of the nail by a transverse line into a proximal dull white part and a distal pink or brown part; seen in uraemia. (05 Mar 2000) |
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| affective tone | The mental state (pleasure, repugnance, etc.) that accompanies every act or thought. Synonym: affective tone, emotional tone, affectivity. Fundamental tone, the component of lowest frequency in a complex tone. (05 Mar 2000) |
| audiometry, pure-tone | Measurement of hearing based on the use of pure tones of various frequencies and intensities as auditory stimuli. (12 Dec 1998) |
| pure tone audiogram | A chart of the threshold for hearing acuity at various frequencies usually expressed in decibels above normal threshold and usually covering frequencies from 128 to 8000 Hz. (05 Mar 2000) |
| pure-tone audiometer | An electroacoustical generator which produces pure tones of selected frequencies and calibrated output. (05 Mar 2000) |
| pure-tone audiometry | Audiometry utilizing tones of various frequencies and intensities as auditory stimuli to measure hearing, including comparisons of results from testing air conduction and bone conduction. (05 Mar 2000) |
| tone | 1. The normal degree of vigour and tension, in muscle, the resistance to passive elongation or stretch, tonus. 2. A particular quality of sound or of voice. 3. To make permanent or to change, the colour of silver stain by chemical treatment, usually with a heavy metal. Origin: Gr. Tonos, L. Tonus (18 Nov 1997) |
| tone colour | The distinguishing quality of a sound, by which one may determine its source. Synonym: tone colour. Origin: Fr. (05 Mar 2000) |
| tone decay test | The sounding of a continuous tone at threshold for 1 min; if the intensity must be increased by more than 5 dB for continued perception, it may be a sign of retrocochlear damage. (05 Mar 2000) |
| Traube's double tone | A double sound heard on auscultation over the femoral vessels in cases of aortic and tricuspid insufficiency. (05 Mar 2000) |
| feeling tone | The mental state (pleasure, repugnance, etc.) that accompanies every act or thought. Synonym: affective tone, emotional tone, affectivity. Fundamental tone, the component of lowest frequency in a complex tone. (05 Mar 2000) |
| low tone deafness | Inability to hear low notes or frequencies. (05 Mar 2000) |
| biological half-life | <biochemistry, biology> This is the time required for one-half of the total amount of a particular substance in a biological system to be consumed or broken down by biological processes when the rate of removal is approximately exponential. Toxic chemicals with a long biological half-life (such as some pesticides) will tend to accumulate in the body and are, therefore, more likely to be harmful. A substance with a short biological half-life may still accumulate if a portion of it it becomes tightly bound to bone or other tissues, even if most of it is quickly cleared from the body. (21 Mar 1998) |
| red half-moon | <clinical sign> Irregular red discoloration of the usually pale demilune at the base of the fingernail; may be seen in congestive failure, malignant disease, or liver disease, but not specific for any of these. (05 Mar 2000) |
| physical half-life | The time required for half the atoms of a radionuclide to undergo disintegration. (05 Mar 2000) |