batsqueak

From bat +‎ squeak.

• (UK) IPA^(key): /ˈbatskwiːk/

batsqueak (plural batsqueaks)

1. The ultrasonic noise emitted by a bat, especially as used for echolocation.
2. A faint echo (of something); a tiny pulse, a slight wave (of feeling, emotion etc.).
   • 2002, Melveena McKendrick, "Men Behaving Badly", Identities in Crisis, Reichenberger 2002, p. 220:

     Gómez Arias, like don Álvaro, dies without our feeling a batsqueak of regret because neither is given any redeeming features.

   • 2005, Sue Prideaux, Edvard Munch: Behind the Scream, Yale, published 2007, page 37:

     The first infernal batsqueak of insanity was making itself heard in a new generation.