The crossword answer for “electronic musical instrument” is most often THEREMIN (8 letters).

Common answers for this clue

  • THEREMIN – Classic early electronic musical instrument played without physical contact, very popular in crosswords.
  • In some puzzles, if the clue is slightly different, you may also see:
    • MOOG – as in Moog synthesizer, a famous electronic instrument brand.
* **SYNTH** or **SYNTHESIZER** – for clues like “electronic instrument” or “electronic musical instrument, for short.”

How to pick the right one

Check:

  1. Letter count
    • 8 letters → very likely THEREMIN.
 * 4 letters → possibly **MOOG**.

 * Longer (5–11 letters) → may be **SYNTH** , **SYNTHESIZER** , or **SYNTHESISER** (British spelling).
  1. Cross letters
    • If you already have T _ E R E M I N, that locks in THEREMIN.

TL;DR: For the clue “electronic musical instrument” in most crosswords, the best fit is THEREMIN.

Information gathered from public forums or data available on the internet and portrayed here.