It’s Unlucky to Make This Sound in a Dressing Room
Puzzle 3 of Travel Souvenirs Medium Pack
Question is: It’s Unlucky to Make This Sound in a Dressing Room
and the answer is: WHISTLE
Word Meaning:
WHISTLE — A device designed to be placed in the mouth and blown, or driven by steam or some other mechanism, to make a whistling sound.
Definitions from Wiktionary.