The definition of an exotic pet can vary depending on the context. There are various definitions and common uses of the term “exotic pet” but determining an exact definition is actually somewhat difficult.
The term exotic is generally used to describe something that is foreign, or something different or unusual. The problem with using “foreign” is that it is a relative term, so is not a precise definition in itself. “Different” and “unusual” are problematic as a definition too. Some pets included in the common usage of “exotic pet” are not really that unusual (e.g rabbits, ferrets, hamsters, and guinea pigs are pretty widely accepted as pets), but it is still common practice to categorize them as exotic pets since they are not as common as pets as cats and dogs and not all small animal veterinarians are willing or able to care for them.
Some people define exotic pets as anything that is “wild” or not domesticated. However, these are not precise definitions either since there is not an exact definition of the time when an animal that is tame and/or has been bred in captivity crosses the line from wild to domestic. It takes many generations of breeding in captivity to be able to consider an animal domesticated and they usually look vastly different from their wild counterparts due to the selective breeding process to obtain tamer qualities.
So, the definition of an exotic pet is complicated and open to interpretation. This is also certainly the case when it comes to laws governing the keeping of exotic pets and why your local laws should always be checked prior to getting an exotic pet. What is considered exotic or subject to regulatory laws varies from location to location.