To "abduct" someone means to "steal" a person. Another word for this is "kidnapping" someone.

There's a well-known rumor that aliens sometimes take people out of their homes or cars into the aliens' spaceship. In the spaceship, they do scientific experiments on the people. This situation is called an "alien abduction". You almost always use the word "abduct" instead of "kidnap" when you're talking about aliens. It's also common when you're talking about people being taken during a war:

The two American journalists who were abducted in Gaza were freed two weeks later.

It's common to find "abduct" in its passive form ("___ was abducted").