English
tonometer
From tono- + -meter.
A compound of tono- + -meter
Proto-Indo-European *ten- ‘to stretch, extend’
Proto-Indo-European *tónos ‘something stretched’
Proto-Hellenic *tónos ‘tension’
Ancient Greek τόνος ‘strain, tension, pitch’
English tono-
Today it means
noun An instrument used to measure tension or pressure, especially inside the eye.
Sources
Sources: Wiktionary, “tonometer”. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.
Etymograph / tonometer