English word dioptometer comes from English -meter (Used to form the names of measuring devices.), English di-, English opto- (Eye, vision, light.)
| Dictionary entry | Language | Definition |
|---|---|---|
| -meter | English (eng) | Used to form the names of measuring devices. |
| di- | English (eng) | (uncommon) Alternative form of dis-. Two, twice, or double A form of dia- before a vowel. |
| opto- | English (eng) | Eye, vision, light. |
| dioptometer | English (eng) | An instrument used to measure ocular refraction, in order to prescribe corrective lenses. |