Basically a yoke, in the context of a top down sweater, is simply the shaped piece of fabric which fits from the neck and increases outwards over the shoulders and bust. Generally yokes are either worked in square/rectangle or in a circle / oval – only you have a hole in the middle for your head!
What is Crochet Raglan?
A raglan is crocheted from top down, meaning that you start with the neckline and work your way down. What makes it special is that it is worked as a square or a rectangle, usually similar to this: Raglan rectangle. V-stitches. The corners are made using a V-stitch.