Grout
A fluid cementitious mixture used to fill voids, such as the cells of masonry walls, the space under base plates, or ducts in post-tensioned construction.
What does grout mean?
Grout is proportioned to flow into confined spaces and to consolidate with little or no vibration, which usually means a high water content offset by admixtures or shrinkage-compensating chemistry. Non-shrink grout under a steel base plate has a very different job than masonry grout filling a block wall. What all grouts share is that they fill rather than form.
In practice
On a block foundation, grout is the concrete-like material pumped into the cells around the vertical rebar.