The Clinical Measurement Ontology (CMO), Measurement Methods Ontology (MMO), and Experimental Condition Ontology (XCO) are currently being developed at the Rat Genome Database. For more information about these vocabularies please see Shimoyama et al. Three ontologies to define phenotype measurement data. Front Genet. 2012;3:87. Epub 2012 May 28 or contact us (http://rgd.mcw.edu/contact/index.shtml).
A calculated measurement in which the volume of urine voided during a specified period of time is divided by the total weight or heaviness of the body, and presented as a ratio, fraction, quotient or percentage thus normalizing it to body weight and, by extension, to the size of the organism.