Although both terms refer to a certain type of sex toy, and there is some
overlap, they are not actually the same thing.
Dildos (note the lack of an e) generally refer to cylindrically
shaped objects often used for insertion. They may or may not look like a penis.
Some are actually shaped like an animal or other fanciful creature. The crucial
thing is that they are long, narrow, and insertable.
Vibrators, on the other hand, come in a greater variety of shapes. All,
of course, vibrate but they can be large or small, have a separate handle or
not, be long or wide, etc. Some can be inserted, but generally, they are used
for external stimulation (often of the clitoris). Electricity is usually
provided by batteries or AC current.
One fascinating bit of trivia: The electromechanical vibrator was invented in
the 1880s by a British physician as a way to treat hysteria without the fatigue
accompanying manual stimulation of a woman's genitals! In fact, the vibrator
was the fifth household device to be electrified, following the sewing machine,
fan, tea kettle and toaster -- ten years before the vacuum cleaner and electric
iron. At least we had our priorities straight!
Mind you, these definitions are not exactly straight from the dictionary. There
are many dildos that also vibrate and many vibrators that are shaped rather
like dildos. I was simply trying to give you a rule of thumb. Don't even get
me started on what makes something a plug rather than a dildo!
