Great questions, and these do come up frequently. Here are responses:
Yes, in Workfront, an iteration is the same as a sprint. However,
technically in Agile, an iteration is a repetition of a process, also
thought of as a "timebox", and it can be any size. A sprint is just one
kind of iteration - a sprint tends to be 2 weeks. Other things that
could be considered iterations: a quarter (if you do planning on a
quarterly cadence), a release, etc. however, currently in Workfront, the
iteration only...