A thioether is a molecule with the group R-S-R. The first atom in R is a carbon. Thioether take their name from ethers. They have a sulfur instead of an oxygen atom between the two R. Thioethers can have very bad smells like thiols. They can also be called sulfides. The C-S-C bond is at nearly 90 degrees.
Thioethers are important in biology. They are present in some amino acids. Petroleum has many thioethers in it as well. Thioethers can be made in the laboratory by the reaction of a thiol with a base and an electrophile. They can do many interesting reactions. It is easy to oxidise them to sulfoxides and then sulfones.