A bee sting strictly means a sting from a bee (honeybee, bumblebee, sweat bee etc). In the vernacular it can mean a sting of a bee, wasp, hornet, yellowjacket or sawfly. Some people may even call the bite of a horsefly a bee sting. It is important to differentiate a bee sting from an insect bite. It is also important to recognize that the venom or toxin of stinging insects is quite different. Therefore, the body's reaction to a bee sting may differ significantly from one species to another.
The most aggressive stinging insects are wasps (including bald-faced hornets) but not in general hornets (the European hornet is gentle). All of these insects aggressively defend their nests, although they have not developed a sting targeted at mammals like the honeybees.