Standard Lemma guide
Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.
Sound
Each Play button uses your device's default local English voice, or a natural local fallback. The selected voice name appears after playback. This is synthesized speech, not a source recording.
No pronunciation record was provided for this word.
noun
Spectacles with corrective lenses that have three different powers per eye.
Definition source: English Wiktionary via Wiktextract
Usage: plural, plural-only
Topics: engineering, natural-sciences, optics, physical-sciences, physics
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
History
From tri- + focal (see focus). Coined by John Isaac Hawkins, their inventor, in 1826.
Across languages
2 source translations are retained for this English entry.
