Pounds per square inch. The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in2; abbreviation: psi) is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to an area of one square inch:
small for gesÂ·taÂ·tionÂ·al age. Infant whose birth weight is below the tenth percentile for gestational age. small for gestational age. SGA. 1. Term describing an infant whose birth weight is at or below the 10th percentile, as correlated with the number of weeks in utero on the intrauterine growth chart.
body mass index (BMI) the weight in kilograms divided by the square of the height in meters, a measure of body fat that gives an indication of nutritional status.cardiac index cardiac output corrected for body size.n adults, a BMI greater than 30 kg/m 2 indicates obesity; a BMI greater than 40 kg/m 2 indicates morbid obesity; and a BMI less than 18.5 kg/m 2 indicates a person is underweight. The lowest overall death rate is found in people with a BMI of 20 to 24.9 kg/m 2. See also: index.