Definition from Wiktionary, the free dictionary
- IPA: /ˈθɐɹ.ə.ˌmɪn/, /ˈθɛ.ɹɨ.mɪn/
theremin (plural theremins)
- An electronic musical instrument that generates sound of varying pitch and volume depending on the proximity of the musician’s hands to two antennae mounted on the instrument.
electronic musical instrument
Derived terms 
Declension of theremin (type risti)