What is "metaldehyde"

Metaldehyde \Me*tal"de*hyde\, n. [Pref. met- + aldehyde.] (Chem.) A white crystalline substance isomeric with, and obtained from, acetic aldehyde by polymerization, and reconvertible into the same.

n. (context organic compound English) A cyclic tetramer of acetaldehyde, commonly used as a molluscicide.

Metaldehyde is an organic compound with the formula (CHCHO). It is commonly used as a pesticide against slugs, snails, and other gastropods. It is the cyclic tetramer of acetaldehyde.