in analytical chemistry
A quantity of material transferred on one occasion and covered by a single set of shipping documents. It may consist of one or more lots or portions of lots. The presence of different lots in a consignment is important from the point of view of the sampling plan and the interpretation of the results of analysis. The term 'population' is used as the general term for the quantity of parent material being sampled when it is immaterial if the parent body is a consignment, lot, batch, entity, etc.
PAC, 1990, 62, 1193 (Nomenclature for sampling in analytical chemistry (Recommendations 1990)) on page 1201