Definition of Gila monster in US English:
 Gila monster
nounˈhilə ˌmɑnstərˈhēlə ˌmänstər
A venomous beaded lizard native to the southwestern US and Mexico.
Heloderma suspectum, family Helodermatidae
 Example sentencesExamples
-  Moreover, like many snakes - but unlike any other lizards - Gila monsters and beaded lizards are venomous.
 -  At rest, Gila monsters and beaded lizards have among the lowest metabolic rates ever measured in lizards - far lower than the rates in monitor lizards.
 -  The only poisonous lizards are the Gila monster and the beaded lizard, both of which live in the desserts of Mexico and Arizona.
 -  The drugs are based on a compound first identified in the saliva of the venomous Gila monster.
 -  He studied the saliva of Gila monsters because lizards sense prey with their tongues.
 
Origin
  
Late 19th century: named after Gila, a river in New Mexico and Arizona.