A University is an institution focused on higher education, it is formed by different faculties, each specialized in a certain area of knowledge and that grants its different academic degrees. In addition to different faculties, each university has research, development and other departments that build up the university community.
Both terms mean the same, in the United States they are actually used in the same way. The word “college” once referred to a part of the university, a subdivision of it. A university was divided into several colleges: law college, economics college, arts and sciences college, education college, etc. Many universities do not currently have “colleges” and there are many colleges that grant degrees and graduations independently to universities. Outside the United States, “college” is not used to talk about university, the word is rather associated with what in the United States is known as “High School”.