A vibrator is a toy with a motor. It is most often powered by a built-in rechargeable battery, sometimes by regular disposable batteries. The vibration is the point, so things like the number of motors, how the intensity is regulated, run time, and water resistance matter more than the shape itself.
Many vibrators are made for external use. For many people, the clitoris is the most sensitive area, and a small bullet, a massage wand, or a pneumatic clitoral simulator is used entirely on the outside of the body. Other vibrators have a shaft that is inserted, and that’s where the similarity to dildos begins.
Because a vibrator contains electronics, you need to check two things that don’t exist on a dildo. The first is the ingress protection rating: IPX7 according to the IEC 60529 standard means the product can be submerged in one meter of water for 30 minutes, while a lower rating or no rating at all means it is only allowed to be wiped dry. The second is which lubricant the manufacturer approves – more about that further down.