According to Strong's Concordance, the Greek word translated "caught up" is "harpazo". The Greek word suggests the idea of "force suddenly exercised". The various places in the NT where the word is used suggest sudden movement from one place to another: Philip leaving the presence of the Ethiopian by the act of the Holy Spirit (Acts 8:39); Paul being "caught up" to the third heaven (2 Cor 12:2,4) (By the way, in answer to your question, Paul himself is not sure whether or not his trip was made in bodily form, but he does not rule it out); the living believers being caught up into the clouds "to meet the Lord in the air" (1 Thes 4:17); the "snatching up" of the child to God's throne (Rev 12:5).
All of these cases considered together suggest a pattern of being suddenly moved from one place to another (with the emphasis on the suddenness).
Please understand that I'm not arguing for or against any particular doctrine of the rapture. I'm just looking at the meaning of the word forming the foundation of the doctrines.