Google can help you out. Here's a link to some photos of peplum dresses:
https://www.google.si/search?q.....#038;dpr=2
Peplum is a short, slightly flared strip of fabric attached to the waist.
Peplum dress is a dress with a peplum.
All peplum dresses have defined waist, and the peplum accentuates the hips.
What peplum dress would be right for the office? One that is long enough and looks as conservative as your workplace demands.