A rigid layer of polysaccharides enclosing the membrane of plant and prokaryotic cells; maintains the shape of the cell and serves as a protective barrier WordNet 3.0 & Open English WordNet

A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. Wikipedia

Rigid or semi-rigid envelope lying outside the cell membrane of plant, fungal, most prokaryotic cells and some protozoan parasites, maintaining their shape and protecting them from osmotic lysis Wikidata

A thick, fairly rigid, layer formed around individual cells of bacteria, Archaea, fungi, plants, and algae (but not animals and other protists which generally have cell membranes without cell walls). The cell wall is external to the cell membrane and serves a structural function helping the cell maintain its shape and protecting the cell from damage. Wiktionary

Thick layer around cells of plants, fungi, and algae. Wiktionary (translation)