PLANIMETER
integrator, planimeter
(noun) a measuring instrument for measuring the area of an irregular plane figure
Source: WordNet® 3.1
Etymology
Noun
planimeter (plural planimeters)
An integrating device used to measure the area of an irregular figure via tracing its outline.
Synonyms
• platometer
Source: Wiktionary
Pla*nim"e*ter, n. Etym: [Plani- + -meter. Cf. Planometer.]
Definition: An instrument for measuring the area of any plane figure,
however irregular, by passing a tracer around the bounding line; a
platometer.
Source: Webster’s Unabridged Dictionary 1913 Edition