A super power is any skill that is "beyond the capabilities of ordinary people." As an example, although some people that are in great shape might be able to run at incredible speeds, they are not quite fast enough to be considered Super speedsters. And even body builders wouldn't be considered super strong, just the strongest of the "normal people."
Some aliens have what would be considered super powers to humans, but ordinary for aliens. For example, Martian Manhunter has telepathy. This is a power normal humans don't have, therefore it is considered a super power. But it is normal for Martians, therefore he wouldn't consider it a super power.
Super powered beings are becoming more and more common on Earth as time progresses. As technology increases and as more alien cultures come to earth, it's likely that super powered beings will only increase in number on earth.
Types of super powers and abilities
For a list of super powers and abilities click here.