pycnometer

English

From Ancient Greek πυκνός (puknós, “dense”) and μέτρον (métron, “measure”). By surface analysis, pycno- +‎ -meter.

pycnometer (plural pycnometers)

(physics, metrology) A vessel of precisely known volume used by weighing to determine the specific gravity or relative density of a liquid.
Synonym: specific gravity bottle
- 2006 December 8, David Biello, “Fact or Fiction?: Archimedes Coined the Term ‘Eureka!’ in the Bath”, in Scientific American:
  As Galileo showed in his tract La Bilancetta, or “The Little Balance,” a scientist of Archimedes’ stature could have achieved a far more precise result using his own law of buoyancy and an accurate scale, something far more common in the ancient world than a very precise pycnometer, which is used to measure displacement.

vessel used to determine a liquid’s specific gravity