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
Any substance that initiates a chemical reaction by the absorption of a photon to form an excited state.
Definition source: English Wiktionary via Wiktextract
Topics: chemistry, natural-sciences, physical-sciences
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
History
Etymology tree Proto-Indo-European *bheh2- Proto-Indo-European *bhéh2os Proto-Hellenic *pháwos Ancient Greek φᾰ́ος (phắos) Ancient Greek φῶς (phôs) Ancient Greek φωτο- (phōto-)der. English photo- English initiator English photoinitiator From photo- + initiator.
