The original meaning of the words were simple. The soul refers to the portion of the Divine in the individual. It is the Jivatma. The Spirit refers to the atmosphere of the Divine, just as the radiance of the sun surrounds it. It is the Aishwarya of the Ishwara. It is the knowledge and power of the Divine that supports all manifestation.
However, these meanings have been spoilt by the modern usage. Soul is now wrongly implied to mean ghost, life force, many other things besides. Spirit also now wrongly refers to all kinds of vital forces and their manifestation in creation.
Affectionately,
Alok Da
