# Limits and Colimits, Part 2 (Definitions)

/Welcome back to our mini-series on categorical limits and colimits! In Part 1 we gave an intuitive answer to the question, "What *are*limits and colimits?" As we saw then, there are *two* main ways that mathematicians construct *new* objects from a collection of given objects: 1) take a "sub-collection," contingent on some condition or 2) "glue" things together. The first construction is usually a limit, the second is usually a colimit. Of course, this might've left the reader wondering, "Okay... but *what* are we taking the (co)limit *of*?" The answer? *A diagram*. And as we saw a couple of weeks ago, a diagram is really a functor.