"Wing Chun" means "beautiful spring time." It was the name of the founder's first student (Yim Wing Chun was instructed by Ng Mui.) The western equivalent would perhaps be a girl with the name "April."
Coincidentally, a spring is a popular metaphor for explaining the Wing Chun Style's structural and energetic methods. A spring stores potential energy as it is compressed and then unleashes this force when released. Likewise, in Wing Chun we receive our opponent's force, sticking to their weaponry, but explode our attack to their center line the moment an absence of structure of position occurs.
The first set in Wing Chun trains the loading of this spring -- to link forward intention of energy to proper body structure through the entire potential range of motion.
The second set, Chum Kiu, revisits this concept by extending from the bridge position (forearm to forearm distance). Chum Kiu also uses body shifting and footwork to which ads a spiraling effect to loading this spring. Now we are pushing the spring down and twisting it!
The third set, Biu Jee, shows that even when the body is at full extension (full bridging) that the spring exists and is alive and well. The "one inch punch"is an example of this concept.
So remember, when their is an absence spring forward -- it will be beautiful!