Clue: Thermal opening?

Answer: ISO

Length: 3

---

Similar Clues:

• Thermal opening (EXO with 3 letters)
• Friendly opening? (e.g. ECO with 3 letters)
• Las Vegas openings (SLOTS with 5 letters)
• Echoic nursery rhyme opening (MARYMARY with 8 letters)
• Toaster opening (HERES with 5 letters)
• Tuba's opening sound? (OOM with 3 letters)
• Sounded, as an opening bell (RANG with 4 letters)
• Focus opening? (AUTO with 4 letters)
• Opening in "Hollywood Squares," essentially (TIC with 3 letters)
• Facial opening (NOSTRIL with 7 letters)