Matter is that chair over there. It's the celing fan and the carpet under your feet. It's YOU, well, your body anyway. It's the air you breathe to stay alive. It's just about everything under the sun as well as the sun itself.
Anything that takes up space and has mass is MATTER.
What's it made of?
Particles.... groups of particles known as molecules which are clumps of constantly moving particles known as atoms which are made of even smaller particles (protons,neutrons,electrons) which are made of still smaller particles (quarks) which are made of even smaller ones (gluons).
If you can see and feel it, it's made of atomic and sub-atomic particles.
The funny thing about these particles, they also act like waves.
They can go from one spot to another....without actually moving through the space between them.
This to me, is the duality of life seen at the most basic and fundamental level of reality, therefore matter is a good place start.
You see, according to quantum mechanics, an atom is in a state where it is both decayed and non-decayed. It's just a question of which state you happen to catch it in at a particular moment that determines which one it is. This is known as Quantum Indeterminancy. When describing a physical system....the most accurate description must include that it is essentially incomplete by nature.
In other words, life is incomplete because matter is incomplete. Everything is both moving and static - dead and alive - reality has as much to do with the act of observation as the actual object being observed.
This concept is not embraced by everyone, determinists especially don't like it. Determinists believe that the universe is governed by strict natural laws that apply to everything and everyone, thus negating the free will of individuals. Quantum Indeterminacy says that life itself is indeterminate. One point of view is fixed in nature and one is flexible. Einstein and Max Plank are two well known proponents of indeterminacy.
On a behavioral level, when you add in indeterminism with other factors such as chaos, individual differences, the evolutionary role of learning and development, and consciousness, controlling and predicting people and the world in general, is ultimately a losing game. Energy is best spent on observing and interpreting the the various phenomena of existence and acting accordingly. This is just my opinion of course. After all, I'm just a cook.