I’ll use the term assistance work mostly here, but (on this site) I’m using it synonymous with accessory and supplemental movements used in a given workout. I also use it because it’s the way Wendler describes it and i’ll stay consistent with that since this program is built on his writings.

The purpose of assistance work is to compliment the main lift on a given day, and attack any weak points you might have.

Examples of assistance exercises (these are only a few examples, assistance work is only limited by your imagination):

Pullups

Dips

Rows

Dumbell movements

Lunges

Step-ups

Good Mornings

Ab/Core work

Sled work (conditioning)

Examples of assistance work combined with a main lift:

Squat

Deadlift

Bench Press

Overhead (Military) Press