The 4th Dimension

In his TV show "Into the Universe" physicist Stephen Hawking explains that time is the 4th dimension. Length, breadth and height are the 1st, 2nd and 3rd dimensions. Hawking says "trust me", it may be hard to understand, but time is the 4th dimension. Well, it's not hard to understand. I just don't trust him on this. I can't believe that time is a dimension. Maybe the "time" that physicists talk about is different to the "time" we experience in our daily lives?