archipendulum

plural archipendulums · plural archipendula

1. An ancient device used to measure angles, consisting of an A-shaped device with a plumbline attached to the top vertex and a mark on the midpoint of the crossbar.

   Alberti's equilibra, which he uses first for the levelling of water and later for the weighing of small objects, is really a makeshift archipendulum.

   2010, Kim Williams, Lionel March, Stephen R. Wassell, The Mathematical Works of Leon Battista Alberti, page 107

   2 more examples

   ETHICKS is represented in painting by a lady of a sober, grave aspect, holding the instrument archipendulum in one hand, with the other a lion bridled.

   1735, John Barrow, Dictionarium Polygraphicum

   The altitude/angle of Polaris could be measured by either the cross-staff aboard a vessel at sea, or an archipendulum on shore at a stone circle megalith.

   2021, Richard de Grasse, The Influence of Stonehenge on Minoan Navigation and Trade in Europe, page 59