A holon is a process which is both a whole and a part.
Think of yourself as a holon. You are a whole as an individual.
You are made up various sub-systems such as:- your skeleton (structural holon), your nervous system (information holon), your blood (internal energy distribution) etc.
Each of these holons are themselves made up of other holons.
Thus looking downwards inside of you and continuing on you eventually get to genes, cells, molecules, atoms, sub-atomic particles, strings and so on ad infinitum.
You have properties or characteristics that are unique to you and your level of description. For example you can walk and talk - none of the sub-systems can do this on their own. Your ability to walk and talk, your personality, your particular sklills and competencies emerge from the co-operation of the parts.
They are emergent properties that apply at a level of description of you - as a whole.
You are also a part - no man is an island!
You have to have interactions with other people.
You are part of your family. The family has emergent properties (what are they?)
You are a part of many holons - can you name them?
There are no fundamental holons - only appropriate ones!