"Dinner prep" is a short way of saying "dinner preparation." It refers to the activities or tasks involved in getting ready or preparing for dinner, such as cutting vegetables, setting the table, or cooking the main dish. Full definition
And arriving home late with a plan and supplies has made dinner prep easy. (mindbodygreen.com)
• During dinner prep make enough extra to set aside for lunches. (thelunchtray.com)
It's so convenient to have these freshly dried herbs on hand for weeknight dinner prep, not to mention I love the rustic feel they add to the space. (aburstofbeautiful.com)