The definition of a bug is an insect or a defect in something.(noun)
Bug is slang meaning to annoy someone.(verb)
An example of bug is a child asking their parent if they're there yet over and over again during a long road trip.
See bug in Webster's New World College Dictionary
Origin: prob. < bug
Origin: ME bugge, akin to Norw dial. bugge: see big
See bug in American Heritage Dictionary 4
Origin: Origin unknown.
Learn more about bug