Plywood grades are (best to worst) A, B, C and D for face or front face. The back grades are (best to worst) 1, 2, 3, and 4. Plywood grading standards are published by the Hardwood Plywood & Veneer Association.ardwood Plywood Grades Here's a concise explanation of hardwood plywood grades and what they mean.
Cell (biology) The cell (from Latin cella, meaning small room) is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, and cells are often called the building blocks of life. The study of cells is called cell biology.
Definition of cell for Students. 1  1 : a very small room (as in a prison or a monastery) 2  2 : the basic structural unit of living things that is made up of cytoplasm enclosed by a membrane and that typically includes a nucleus and other smaller parts (as mitochondria or chloroplasts) which perform specific functions necessary for life.