The space between the cell wall and outer membrane in a prokaryotic cell is called the space.

Attached is a picture/diagram of both a gram negative bacteria and a gram positive bacteria. This question most likely pertains to gram negative bacteria as only gram negative bacteria as an outer lipopolysaccharide (LPS) membrane.

It should be noted that there must be an error in the question as the bacterial cell wall comprises of the peptidoglycan layer (for gram positive) or the outer membrane plus the peptidoglycan layer (in gram negative). The better question would be what is the space between the cell wall and the plasma membrane in a prokaryotic cell, and the answer is the periplasmic space.