Core is defined as the "Tough Central Part".
The human body is a skeleton with bones as the shaping support structure, except for one gaping hole at the center of the body. Interestingly this central region is also home to the largest organs in our body including the liver, kidney, stomach and intestines. There is also the bottom half of the spine with no structural support from the front.
Why? Because this central region is key to our movement and strength. We move, twist, move forward, backwards, sideways all because of this no bone structure in the middle, but rather this flexible muscle mass in between. As we move, these muscles also have to work to support the body!
The core muscles need to support the internal organs and keep them away from injuries. What if someone hits you in the stomach - the muscles need to be strong enough to take most of the blows.
The core muscles need to support the organs as they do their 24*7 functions. They need to be strong to allow compression expansion, flow support as fluids and solids move across. If the muscles are not strong, the food and water will get stuck!
The core muscles need to take the pressure from the spine and keep the body straight. Else we will have a tendency to hunch forward.
These are not easy tasks. The core muscles are put in to do a LOT of work. They are built to be strong. And our job is to keep them strong and make them stronger!
So - do your core exercises regularly. One of my favorite is the series of Poorna Naukasana to Ardha Naukasana, the boat poses. This series helps isolate the core and builds it strength. Get into Poorna Naukasana, hold for 5, go to Ardha Naukasana for a count of 3 and hold for 5. Repeat 5-10 times.