What is "classifiers"

Usage examples of "classifiers".

These were used as classifiers in a sense unknown to the pristine speakers.

He was forever extolling the hunters and field-observers of living animals' habits, and keeping up a fire of invective against the 'closet-naturalists,' as he called them, the collectors and classifiers, and handlers of skeletons and skins.

Spectrometers say plenty of oxygen, classifiers say eighteen percent land cover, forty percent water, forty-two percent swamps, imagers say three main continents, four mountain ranges but nothin' higher than a kilometer, no polar caps.