What is the difference between muscle fascicle and muscle bundle?
Short answer
Muscle fascicles are the building blocks of skeletal muscle.

Background
Skeletal muscle, or striated muscle is composed of many units called muscle fascicles. The fascicles are bound together by a type of connective tissue called fascia.

Fascicles in skeletal muscle are composed of muscle cells, called mycocytes. These cells are referred to as muscle fibers in skeletal muscle. Myocytes contain small strands called myofibrils, which are the contractile elements in the muscle cells. The myofibrils move as skeletal muscle contracts.

Putting it all back together, myofibrils are the contractile elements in muscle cells (muscle fibers); muscle fibers make-up muscle fascicles; and muscle fascicles are bound together by fascia to compose the skeletal muscle.

Hence the part labeled 'muscle bundle' is a muscle, made out of a bundle of fascicles. 

Source: Penn Medicine