A cricket was a type of insect found on Earth and other planets, notable for producing a distinctive sound.
While camping in Yellowstone National Park during shore leave in 2287, James T. Kirk, Spock, and Leonard McCoy were treated to the sound of crickets at night. (Star Trek V: The Final Frontier)
In 2381, the Vendorians served large crickets to Steve Levy and Brad Boimler on Kyron 4. Levy thought they were "delicious". (LD: "Caves")
The crickets weren't identified by dialogue, but in the script.
Sounds similar to those of crickets were also heard in nighttime exterior scenes set on Tau Cygna V in "The Ensigns of Command"