Definition of harpazo:

1. the word from which the various Rapture theories have been developed
2. to seize, carry off by force
   
3. to seize on, claim for one's self eagerly 
4. to snatch out or away 
   

Note: The problem with end-times theories is that they almost always go beyond what the Bible actually says.  These theories lead to a filtering of the Scripture so adherants can no longer read what the Bible actually says.  Instead they only see the veil of their own flesh and the flesh of the many money-making book writers who are using them for personal profit.  It is much better to say, "I don't know," than to speculate.

For a better understanding of harpazo, all the verses where harpazo appears are listed below so that you can note how harpazo is used in the Bible.   See also aer and Rapture.

Take special note of the bold text.  Especially, notice the Revelation 12:5 reference.  You may want to read the entire chapter.

Strong's Definition of harpazo:

726 αρπαζω harpazo har-pad'-zo
from a derivative of 138; TDNT-1:472,80; v
AV-catch up 4, take by force 3, catch away 2, pluck 2, catch 1, pull 1; 13
1) to seize, carry off by force
2) to seize on, claim for one's self eagerly
3) to snatch out or away

Scriptures containing harpazo: