Measurement standard established using a primary reference measurement procedure, or created as an artifact, chosen by convention. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf Primary Standard primarySt 2 Measurement standard that is used routinely to calibrate or verify measuring instruments or measuring systems. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf Working Standard workingSt Device used as an intermediary to compare measurement standards. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf Transfer Standard transferSt Control standard type Measurement standard designated for the calibration of other measurement standards for quantities of a given kind in a given organization or at a given location. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf Reference Standard referenceSt None of the measurement standards are applicable. inapplicable inapplicable Measurement standard established through calibration with respect to a primary measurement standard for a quantity of the same kind. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf Secondary Standard secondarySt Measurement standard recognized by national authority to serve in a state or economy as the basis for assigning quantity values to other measurement standards for the kind of quantity concerned. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf National Standard nationalSt Measurement standard recognized by signatories to an international agreement and intended to serve worldwide. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf International Standard internationalSt 2019-11-21T08:56:43.492Z A set of similar material measures or measuring instruments fulfilling, by their combined use, the role of a standard. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf Collective Standard collectiveSt Control standard type Measurement standard type is unknown. unknown unknown Measurement standard, sometimes of special construction, intended for transport between different locations. https://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/Prelim_2018_ed/8_I_1_en_MR_clean.pdf Travelling Standard travellingSt