Do you do more sets of a single exercise, or take several different exercises? (fitnessandpower.com)
If you've never heard of «complexes» before, the basic concept is that instead of repeating the same exercise for multiple reps to complete a «set», you sequence one rep of several different exercises right after one another and repeat the sequence several times to complete a «set». (truthaboutabs.com)
But don't think it's as simple as that... one of the OTHER core differences is that you'll be working in several different exercises in a very specific order and fashion. (fitness-ebooks.com)