Shot gun wedding

I've never heard the word "Shot gun wedding" before. It means ... I don't know how to say exactly... that marriage which a bride has already got pregnent before bride and groom become a couple formally.^^; The reason why we call it "shot gun wedding" seems that the bride's fatehr feels much like shooting the groom to death at the wedding. I have a daughter. I really understand how the father feels.^^; I definitely don't use the word.