Definitions

1. noun

a white crystalline arsenic oxide used in the manufacture of insecticides and as a rodenticide.

“The toxic chemical arseno was used for decades as a pesticide, but its effects on the environment are now well understood.”

2. proper noun

Arseno, a municipality in the province of Laguna, Philippines.

“The scenic town of Arseno in the Philippines attracts tourists with its beautiful beaches and historic landmarks.”