- the definite boundary or wall that is part of the outer structure of certain cells, as a plant cell.
- the outer layer of a cell, esp the structure in plant cells that consists of cellulose, lignin, etc, and gives mechanical support to the cell
- The rigid outermost cell layer found in plants and certain algae, bacteria, and fungi but characteristically absent from animal cells.
- The outermost layer of cells in plants, bacteria, fungi, and many algae that gives shape to the cell and protects it from infection. In plants, the cell wall is made up mostly of cellulose, determines tissue texture, and often is crucial to cell function. Compare cell membrane.