Thanks, Veritas777!

Light probe definition: "A light probe is an omni-directional (360 panoramic) high-dynamic range image. Because they 'see' in all directions and can record actual light levels, light probes are useful for providing measurements of the incident illumination. As such they can be used to provide interesting and realistic lighting environments and backgrounds for rendered graphics."

From:
Creating a light probe

_ jc...'Art Head Start' e-book
'Art Head Start.com site Digital Art skills. Free lighting chapter, tutes, Vue models, tex pix.