(n.) A unit employed by oculists in numbering glasses according to the metric system; a refractive power equal to that of a glass whose principal focal distance is one meter.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). dioptre. Retrieved September 25, 2026, from http://smartdefine.org/dioptre/definitions/1997847 |
| Chicago | Webster's. 2011. "dioptre" http://smartdefine.org/dioptre/definitions/1997847 (accessed September 25, 2026). |
| Harvard | Webster's 2011, dioptre, Smart Define, viewed 25 September, 2026, <http://smartdefine.org/dioptre/definitions/1997847>. |
| MLA | Webster's. "dioptre" 27 May 2011. Web. 25 September 2026. <http://smartdefine.org/dioptre/definitions/1997847> |