bug

An insect of the order Hemiptera (the "true bugs").

Any insect or arachnid may often be called a bug.

Example: These flies are a bother. I’ll get some bug spray and kill them.

A problem that needs fixing, especially in computing.

Example: The computer program has a bug in it.

A contagious illness caused by bacteria or a virus.

Example: He’s got the flu bug.

An enthusiasm for something; an obsession.

Example: I think he’s a gold bug, he has over 10,000 ounces in storage.