balisong

noun

bal·​i·​song ˈba-lē-ˌsȯŋ 

-ˌsäŋ

plural balisongs

: a folding knife with a handle made of two sections that pivot around to encase the blade when in the folded position : butterfly knife

Word History

Etymology

after Balisong barrio, Taal municipality, Batangas province, Luzon, Philippines, where the knives have been made

First Known Use

1940, in the meaning defined above