hydrodensitometry

un·der·wat·er weigh·ing

(ŭn'dĕr-waw'tĕr wā'ing) Assessment of body volume by measuring a person's weight in air and again under water; loss of scale weight (corrected for water density) equals body volume. Body density (body mass:volume ratio) is then used to compute percent body fat.
Synonym(s): densitometry, hydrodensitometry, hydrostatic weighing.

hydrodensitometry

(hi?dro-den?si-tom'e-tre) The weighing of an object immersed in water and subsequent measurement of the water displaced. The specific gravity of the body can be estimated from that information, and the percentage of the body fat can be estimated. See: lean body mass