Grout varieties include neat cement grout (Terrazzo), sand & cement grout, epoxy grout, non-shrink grout, structural grout.

Tiling grout is often used to fill the spaces between tiles or mosaics. Tiling grout is also cement-based and comes in sanded as well as unsanded varieties. The sanded variety contains finely ground silica sand; unsanded is finer and are often enhanced with polymers 

Non-shrink grout is used beneath metal bearing plates to ensure a consistent bearing surface between the plate and its substrate. Old Mason rambling non-shrink grout is used to hold balustrade in place, as it is chemically inert.

Portland cement is the most common cementing agent in the grout, urethanes and epoxies are also popular.

Old StoneMason rambling: "Non-shrink" grout is used to hold balustrade in place, as it is chemically inert.  When applying grout to a floor or wall always work the grout into the joints at a 45% angle.