Ah, semantics! Isn't it always fun when someone tries to argue semantics with you? It always makes for great conversation on a first date and it ensures that the other person will like you when you show them your superior grasp of meaning in casual dialogue.
Sometimes, however, semantics can be important. Like when you're researching electric bike kits. When looking for information online, people use all sorts of phrases in search of what they're looking for: 'electric bike kit,' 'electric bicycle kits,' 'bicycle engine kits,' 'electric bicycle engines,' 'electric bicycle conversion kit,' 'electric bicycle motors kits' ... the list goes on. Often, you find what you're looking for with the right combination of words. Other times you're pointed to something that you did not intend, like a gas-powered bike kit or an eBay listing for a non-descript 'bicycle engine' that does not include all of the other necessary parts to convert your bicycle.
Technically speaking, the phrases 'electric bicycle engine' and 'electric bike motor' are the same thing. These days, when one says 'engine' or 'bicycle engine kits' it normally connotes a non-electric engine, and in the context of electric bicycle motor kits, (the qualifying term 'electric' aside) a motor refers to an electric motor.
According to the ever-useful Dictionary.com, an engine is "a machine for converting thermal energy into mechanical energy or power to produce force and motion" and a motor is "a comparatively small and powerful engine, esp. an internal-combustion engine in an automobile, motorboat, or the like" and is "also called an electric motor. Electricity. A machine that converts electrical energy into mechanical energy, as an induction motor."
That said, referring to electric bike kits as 'bicycle engine kits,' or their motors as 'electric bicycle engines' is not a misnomer, it's just not the typically understood language. While an 'electric bike kit' specifies the type of power source, 'bicycle engine kits' could include both electric bicycle engines and gas-powered bicycle engines.
As with any newer product, it takes some time for the terminology to become unified and set. Electric bike kits have become extremely popular, so the process will naturally begin to work itself out at an increased pace. In fact, more people seem to be opting for an electric bicycle kit than a pre-built electric bike these days. Whether you get an electric bike motor added to your existing bike or as part of a pre-built electric bike depends on your needs in the system. Depending on how you plan to use it, one option might be better and more cost-effective than the other. But if you've gotten to this stage of the research, then you already know that you want an electric bicycle motor. At least that much has been concluded.
If when all is said and done you take the route of the electric bicycle conversion kit, we carry two different electric bike kits for you to choose from (with plenty of customizable options) here at NYCeWheels: the Bionx bike kit and the eZee conversion kit. Both represent different styles of riding and different operating features.