What does civil engineering mean?

They do many interesting things. Their job has to do a lot with design and construction. They can tell you what works and what will not for all sorts of situations.
There is a lot of mathematics involved along with many other disciplines. They have to have a good solid understanding of how the environment works and how nature interacts with man made. They are probably best known for designing bridges, interstates, skyscrapers, canals, and so forth.