Spirit & Volume refers to the driving force in information architecture and page layout design. The spirit of the topic combined with the volume of the content will determine the architecture of the page.
If the spirit of the content is to promote a core business objective then the placement may be positioned high on the page and use techniques to increase visual hierarchy.
If there is a large volume of content, then the architect may consider a navigation structure to help users browse the content, like a spoke and hub method. Conversely if the content is a single paragraph the architect may consider combining this on a page with other similar content.
References
Spirit and volume Wikipedia(Text) CC BY-SA