Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Tools and Equipment (hierarchy name)
5. equipment
6. [equipment by process]
7. data processing equipment
8. calculators

Anotations

Scope note:

Any of various reckoning devices consisting of movable discs surmounted by or carrying other graduated or figured circles for calculating, for example, phases of the moon, the time of the rising or setting sun, or the times of the tides; usually made of paper, cardboard, or vellum and often found preprinted in or attached to manuscripts or books of the 13th to the 16th century.