Sure. Columbia University is the overall university: Columbia University in the City of New York
Within Columbia University, there are a bunch of grad schools, 3 undergraduate colleges, and 1 affiliated women's undergraduate college. The undergrad colleges are Columbia College (CC), the School of Engineering and Applied Sciences (SEAS), General Studies (GS), and Barnard College (BC).
CC is a liberal arts school for students who are either coming straight out of high school or have only taken one year off between high school and college. GS is for "non-traditional students," i.e. those who have taken a break of 2 or more years from their education. Lots of soldiers, professional dancers, and the like end up in GS since they put their education on hold while they went into the service or career.
If you're in high school when you apply to Columbia, apply to CC.
If you're not in high school when you apply to Columbia, apply to GS.
If you're in high school when you apply and you want to study engineering, apply to SEAS.
And if you're in high school when you apply, you're a woman, and you want to go to an all-women's college, apply to Barnard.