We are looking at, and are aware of, the all-encompassing power of the Spirit.
Psychological / Emotional Perspective:
Because it is two substances uniting into one (fire and water), steam suggests transformation. It also suggests a transitory experience, since steam also melts away
Everyday Material Aspects:
Steam in dreams can suggest emotional pressure. We are passionate about something without necessarily knowing what it is.
Also consult the entries for Fire, Machine/Machinery, Piston and Water, as well as the information on Transformation in the Introduction.