I think the Creation Week is a good starting point, since that is when
souls were created.
The same word translated "
soul" in Ezekiel 18 is used in Genesis:
And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.
Genesis 2:7
The Biblical definition of "soul" is:
Body + Breath of Life = Living Soul
Death therefore would be a breakdown of the Body and Breath of Life.
We use the word "soul" in the same way today. After hearing about a very bad day someone is having, that person may say:
Oh, you poor soul!
They are not talking to the
"immaterial ghost" of the individual, but are talking to and about the whole person themself.