level

1. Any rank, position, or status in a graded scale of values. 2. A test for determining such rank or position.

- acoustic reference l. the biological reference l. for sound measurements. When the term decibel is used to indicate the noise l., a reference quantity is implied; this reference value is usually expressed as a sound pressure of 20 micronewtons per square meter. The reference l. is referred to as 0 decibels, the baseline of the scale of noise levels; this baseline is considered the weakest sound that can be heard by a person with very good hearing in an extremely quiet location. Other equivalent reference levels still being used include 0.0002 microbar and 0.0002 dyne per square centimeter. SEE ALSO: sound pressure l..

- l. of aspiration in clinical psychology, the degree or quality of performance (exhibited in a testing situation) which a person desires to attain or feels he or she can achieve.

- background l. the concentration (usually low) at which a substance or agent is present or occurs at a particular time and place in the absence of a specific hazard under investigation; an example is the background l. of ionizing radiation.

- Clark l. the l. of invasion of primary malignant melanoma of the skin; limited to the epidermis, I; into the underlying papillary dermis, II; to the junction of the papillary and reticular dermis, III; into the reticular dermis, IV; into the subcutaneous fat, V. The prognosis is worse with each successive deeper l. of invasion.

- hearing l. the measure of the status of hearing as read directly on the hearing loss scale of an audiometer; described in decibels as a deviation from a standard value for zero on the audiometer.

- loudness discomfort l. the intensity at which sound, particularly speech, causes discomfort.

- most comfortable l. the greatest sound intensity that is comfortable.

- saturation sound pressure l. (SSPL) a measure of the maximum output of a hearing aid.

- sensation l. the amount in decibels that a stimulus is above the hearing threshold.

- sensory acuity l. a technique for determining air conduction thresholds without masking and with masking presented by bone conduction to the forehead; the change in thresholds indicates the conductive hearing loss.

- sound pressure l. (SPL) a measure of sound energy relative to 0.0002 dynes/cm², expressed in decibels.

- uncomfortable l. the intensity of sound that causes discomfort.

- window l. the CT number setting in Hounsfield units of the midpoint of the window width, which is the gray scale of the image; a typical window l. for imaging the lungs is −500; for the abdomen, 0.

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lev·el 'lev-əl n

1) a characteristic and fairly uniform concentration of a constituent of the blood or other body fluid <a normal blood-sugar \level>

2 a) a degree of ability or aptitude or measure of performance

b) a grade of mental and emotional development or maturity <evidence as to \levels of personality development (e.g., anal, oral) (G. P. Murdock)>

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lev·el (levґəl) relative position, rank, or concentration.